Flora Malesiana, Series II, Volume 4 (2012) 123 –136

Oleandraceae
(P.H. Hovenkamp, Leiden, The Netherlands & Boon-Chuan Ho, Bonn, Germany)

Oleandraceae Ching ex Pic.Serm., Webbia 20 (1965) 745; K.U.Kramer in K.U.Kramer

& P.S.Green, eds., Fam. Gen. Vasc. Pl. (1990) 190; A.R.Sm. et al., Taxon 55 (2006)
718; Hovenkamp & B.C.Ho, PhytoKeys 11 (2012) 1. — Type genus: Oleandra Cav.
The simple morphology of Oleandra has made comparison with other ferns difficult,
and its position has been judged to be with Dryopteridaceae or Davalliaceae, where it
has been associated in particular with Nephrolepis and Arthropteris (Copeland 1947;
Holttum 1959; Nayar & Bajpai 1978). Holttum (1959) included Oleandra with Nephro­
lepis and Arthropteris in an informal Nephrolepis-group. More recent views (Tryon &
Tryon 1982; Kramer 1990; Tryon & Lugardon 1991) exclude Nephrolepis, and molecu-
lar studies (Kuo et al. 2011; Schuettpelz & Pryer 2007) indicate that these three genera
do not form a clade, but that they are each associated with a different clade in the crown
leptosporangiates. Here we treat Oleandraceae as a monogeneric family, with the single
genus Oleandra.
References: Copeland, E.B., Gen. Fil. (1947). Chronica Botanica, Waltham, Mass. — Holttum, R.E.,
in C.G.G.J. van Steenis (ed.), Flora Malesiana, Ser. II, 1 (1959). Nijhoff, Dr. W. Junk, The Hague,
Boston, London. — Kramer, K.U., in K.U. Kramer & P.S. Green (eds.), Fam. Gen. Vasc. Pl. (1990).
Springer, New York etc. — Kuo, L.-Y., F.-W. Li, W.-L. Chiou & C.-N. Wang, First insights into fern
matK phylogeny. Molec. Phylogenet. Evol. 59 (2011) 556 – 566. — Nayar, B.K. & N. Bajpai, Morphol-
ogy in relation to phylogeny of the Davallioid-Oleandroid group of ferns. Phytomorphology 26 (1978)
333 – 354. — Schuettpelz, E. & K.M. Pryer, Fern phylogeny inferred from 400 leptosporangiate species
and three plastid genes. Taxon 56 (2007) 1037–1050. — Tryon, A.F. & B. Lugardon, Spores of the
Pteridophyta (1991). Springer, New York etc. — Tryon, R.M. & A.F. Tryon, Ferns and allied plants,
with special reference to tropical America (1982). Springer, New York etc.

Taxonomy

The genus Oleandra was described by Cavanilles (1799, 1802) who derived both the
genus name and the species name from Nerium oleander L. (Apocynaceae). From this
it should be clear that he only saw the aerial stems of Oleandra neriiformis, of which
the forms with distinctly whorled fronds are indeed strongly reminiscent of branches
of Nerium oleander. Oleandra was included in Aspidium by Swartz (1801, 1806), but
reinstated by Presl (1836) and John Smith (1841, 1842), and the distinctness of the ge-
nus has not been questioned by subsequent authors while only one author has preferred
to recognize Oleandra at subgeneric level (Splitgerber 1840).
There is as much unanimity on the distinctness of the genus as there is uncertainty on
the number and distinctness of the species that can be distinguished in Oleandra, and
many authors who have tried to deal with the genus have commented on the difficulties
of species delimitation. Kramer (1990) estimated the number of species to be 40 (“many
species are similar in appearance”) and Pichi Sermolli (1965) gives a number of 50
(“the delimitation of the species is not always easy, since some of them show a high
degree of polymorphism”)”. Hovenkamp & Ho (in press) distinguish 9 species in Asia,
of which 7 occur in Malesia.
124 Flora Malesiana, Ser. II, Vol. 4 (2012)

References: Cavanilles, A.J., Anales Hist. Nat. 2 (1799). Imprenta real, Madrid. — Cavanilles,
A.J., Descripcion de las plantas (1802). Imprenta real, Madrid. — Hovenkamp, P. & B.-C. Ho, Ole-
andra (Pteridophyta, Oleandraceae) in Asia. Blumea (in press). — Presl, C.B., Tent. Pterid. (1836).
Theophilus Haase, Prague. — Smith, J., Enumeration Filicum Philippinarum. J. Bot., London III
(1841) 393 – 422. — Smith, J., An arrangement and definition of the genera of Ferns, with observa-
tions on the affinities of each genus. J. Bot., London 4 (1842) 38 –70. — Splitgerber, F.L., Enumera-
tio Filicum et Lycopodiacearum quas in Surinamo legit F.L. Splitgerber. Tijdschr. Natuurl. Gesch.
Physiol. 7 (1840) 411. — Swartz, O., Genera et species filicum ordine systematico redactarum. J.
Bot. (Schrader). Göttingen 1800 (1801). — Swartz, O., Synopsis Filicum (1806). Bibliopolii novi
academici, Kiel.

Morphology and characters

The morphology and anatomy of Oleandra has been studied by various authors (Ogura
1939; Wetter 1951; Phillips & White 1967; Sen & Sen 1973; Nayar & Bajpai 1978),
mainly with an emphasis on the structure of the rhizome, of which the climbing habit
in some species is a striking character.
Much of the variability between species in Oleandra is found in the rhizome, but
as large parts of the rhizome are usually not preserved in herbarium collections, it is
difficult to appreciate and describe this variability. In the Malesian species, rhizomes
may be relatively short-creeping, leading to more or less compact clumps of fronds,
or more widely creeping. In the latter case, in some species the rhizome appears to be
short-lived, decaying less than 1 m behind each growing point, which leads to stands
with a scattered growth of plants. In others, the rhizome can be highly persistent, and
stands may be extensive, with a dense growth of stems. In plants with this growth form,
parts of the rhizome may also grow outwards or upwards from the substrate and form
erect or drooping stems, here to be called ‘aerial’ stems, that are often rootless. This
is the shrubby growth form that is most often associated with the genus, although it
occurs only in a minority of species. Branches are often opposite each other, and then
both branches follow the same growth, either downwards (positively geotropic) or up-
wards (negatively geotropic). The anatomy shows a variably, but often very strongly
developed peripheral sclerified sheath, a ground tissue with or without scattered scle-
renchyma strands, and a dictyostele.
The rhizome is covered with usually persistent rhizome scales with a peltate attach-
ment. The scales are often strongly thickened near the attachment, and the margin can
be nearly entire or densely set with woolly hairs (best visible in young scales) or sessile
glands. The scales are strongly appressed or spreading to recurved – in the latter case
the recurved parts tend to disappear on older rhizomes, giving the impression of a cover
of short, appressed scales.
Roots arise mostly from the ventral side of the rhizome, and may be unbranched for a
considerable length. The long unbranched parts have been described as rhizophores, but
were identified as real roots by Wetter (1951). Branching associated with the formation
of root hairs occurs presumably when the roots are in contact with a suitable substrate,
and thus the unbranched parts tend to be more evident in species that creep over the
substrate, often at some distance, or over dense cushions of moss, than in species with
a subterraneous rhizome.
Hovenkamp & Ho — Oleandraceae 125

Fronds arise on the rhizome without any apparent regularity, often clustered in more
or less distinct whorls or clumps, but on creeping rhizomes often also more widely
separated. They do not appear to grow in regular series, but are inserted more or less
dorsally on creeping stems, and often on all sides on aerial stems. At a variable position
on the stipe, there is a distinct articulation point, where old fronds abscise cleanly. The
lamina is uniformly simple in all species, and varies little in shape, except in O. wer­
neri where the fronds are distinctly dimorphic, with the fertile fronds or parts strongly
contracted. Sori are indusiate with a reniform indusium, and always separate. They
are borne dorsally and singly on the veins, at distances from the costa that may vary
strongly. Sporangia are long-stalked, often with a number of glandular hairs attached
to the distal part of the stalk, just below the capsule. The capsule is of the common
Polypodiales type.
The spores of Oleandra have been studied with SEM by Liew (1977), Tryon & Lu-
gardon (1991) and Hovenkamp & Ho (in press). The morphology of the spores of the
Malesian species is highly variable but essentially uniform, and the variation can be
described in terms of a restricted number of parameters.
The spore wall is composed of a smooth exospore, and a thick but hollow and often
highly ornamented perisopre. The surface of the perisopre shows a pattern of coarse
folds, a variable ornamentation and a variable degree of perforation. The folds may be
broad, narrow, or replaced by elongated fissures, the ornamentation ranges from warty
to densely spinose. This surface may be perforated or perforated to varying degrees,
exposing an inner structure of numerous narrow cylindrical pillars c. 0.5 μm thick.
These pillars are attached to a thin basal layer that adheres closely to the exospore. In
the extreme case, the outer surface is so strongly perforated that the entire perispore
consists of an open mesh. Within this range of variability, most species that could be
studied with an adequate sample of specimens show variability in 2 or more of these
parameters, and it is difficult to identify character states that are characteristic for one
species, although it appears that O. sibbaldii has a more consistently highly perforated
perispore than the other species.
The size of the spores of a single specimen varies from c. 35 – 45 to 60 –70 μm, also
between specimens of one species.
References: Hovenkamp, P. & B.-C. Ho, Oleandra (Pteridophyta, Oleandraceae) in Asia. Blumea
(in press). — Liew, F.S., Scanning electron microscopical studies on spores of Pteridophytes. 11.
The family Oleandraceae (Oleandra, Nephrolepis and Arthropteris). Gard. Bull. Singapore 30 (1977)
101–110. — Nayar, B.K. & N. Bajpai, Morphology in relation to phylogeny of the Davallioid-Olean-
droid group of ferns. Phytomorphology 26 (1978) 333 – 354. — Ogura, Y., Anatomy and morphology
of Oleandra wallichii (Hk.) Pr., with some notes on the affinities of the genus Oleandra. J. Jap. Bot. 9
(1939) 193 – 211. — Phillips, D.A. & R.A. White, Frond articulation in species of Polypodiaceae and
Davalliaceae. Amer. Fern J. 57 (1967) 78 – 88. — Sen, U. & T. Sen, Anatomical relationships between
the Oleandra and Nephrolepis groups. Bot. J. Linn. Soc., Suppl. 1 (1973) 155 –172. — Tryon, A.F.
& B. Lugardon, Spores of the Pteridophyta (1991). Springer, New York etc. — Wetter, C., Über die
Luftwurzeln von Oleandra. Planta 39 (1951) 471– 475.
126 Flora Malesiana, Ser. II, Vol. 4 (2012)

Karyology

Chromosome numbers have been established for the Malesian species O. musifolia
and O. neriiformis (Löve et al. 1977) but not on basis of Malesian specimens. In both
species, the number was diploid with n = 41. The variability in spore size may be an
indication of the presence of different ploidy levels (Harmata & Kornás 1978).

References: Harmata, K. & J. Kornás, Spore morphology in two varieties of Oleandra distenta
Kunze (Davalliaceae, Filicopsida) from southern tropical Africa. Zesz. Nauk. Uniw. Jagiellon. Prace
Bot.: 493 (1978) 8 –14. — Löve, A., D. Löve & R.E.G. Pichi Sermolli, Cytotaxonomical atlas of the
Pteridophyta (1977). Cramer, Vaduz.

Distribution

Oleandra is pantropical, but all the individual species are more limited in distribution.
Some of the Malesian species extend to Continental Asia, Australia or the Pacific. One
is endemic to Borneo, and two are restricted to New Guinea and the surrounding islands.

Oleandra
Oleandra Cav., Anales Hist. Nat. 1 (1799) 115; Descr. plant. (1802) 252; Backer & Posth., Varenfl.
Jav. (1939) 86; Copel., Gen. Fil. (1947) 90; Fern Flora of the Philippines 1 (1958) 180; Holttum,
A revised Flora of Malaya II. Ferns. Ed. 2 (1968) 383; Tagawa & K.Iwats., Fl. Thailand 3. Pteri-
dophytes (1985) 179; G.H.Bell, Flora of Australia 48 (1998) 445; Lumbreras, Flora Montiberica
28 (2004) 19. — Aspidium Sw. subg. Oleandra Splitg., Tijdschr. Natuurl. Gesch. Physiol. 7 (1840)
411. — Type: Oleandra neriiformis Cav. (‘neriformis’).
Ophiopteris Reinw., Sylloge plantarum novarum … 2 (1825) 3. — Type: Ophiopteris verticillata Reinw.
= Oleandra neriiformis.
Neuronia asplenioides D.Don, Prodr. Fl. Nepal. (1825) 6. — Type: Neuronia asplenioides D.Don =
Oleandra wallichii.

Terrestrial, epilithic or epiphytic, creeping or scrambling ferns. Rhizome scaly, roots

scattered, often with long rhizophore-like proximal parts, fronds scattered or in whorls,
on stipe-like phyllopodia, dehiscing at a slightly thickened articulation point. Fronds
stipitate, lamina simple, margin entire, veins distinct, somewhat raised on both sides,
1– 2 times forked at or near the costa, costa often with narrow scales, lamina and veins
often with acicular or capitate hairs. Sori in one, often irregular row on each side of
the costa, with a more or less reniform, glabrous or hairy indusium. Sporangia stalked,
stalk often with a number of sessile or stalked glands below the sporangium, sporan-
gium body glabrous, spores monolete, perispore with broad wings, sometimes highly
perforate, or echinate, massive.

Key to the species

1a. Rhizome with stiff, erect to pendent rootless aerial branches . . . . . . . . . . . . . . . . 2

b. Rhizome creeping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2a. Fronds strongly dimorphic, scattered on the rhizome or somewhat clustered on short
side branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. O. werneri
Hovenkamp & Ho — Oleandraceae 127

b. Fronds monomorphic or slightly dimorphic, often in whorls of 5 –10 fronds . . . . 3

3a. Lamina thick, coriaceous, costa below with copious, conspicuous, 3 – 4 mm long
pale to brown scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. O. coriacea
b. Lamina thin, papyraceous when dry, costa below mostly with few or inconspicuous
scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. O. neriiformis
4a. Rhizome in older parts not entirely covered with scales; scales with squarrose acu-
men and entire or distinctly glandular margin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
b. Rhizome entirely covered with overlapping scales, scales with appressed or spread-
ing apex, usually with non-glandular cilia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5a. Rhizome scales with gradually narrowed apex, stipe 0.5 – 4.5 cm long, costa and
stipe often with distinct dark coloration . . . . . . . . . . . . . . . . . . . . . 5. O. sibbaldii
b. Rhizome scales with abruptly narrowed apex, stipe to 2 – 3 mm long, costa and stipe
without dark coloration below . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. O. vulpina
6a. Phyllopodia very short, inconspicuous, much shorter than the stipe, sori mostly in
a closely costal single row . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. O. musifolia
b. Phyllopodia longer, position of sori variable . . . . . . . . . . . . . . . . . 2. O. cumingii

1. Oleandra coriacea Copel.

Oleandra coriacea Copel., J. Straits Branch Roy. Asiat. Soc. 63 (1912) 72. — Type: Moulton s.n.
(SAR?, n.v.), Borneo.

Rhizome with creeping parts unknown, aerial stems unbranched and rootless, 2 – 3
mm thick (when dry), bearing in cross-section with a distinct sclerified peripheral sheath
and few, scattered sclerified strands, not white waxy, fronds in weak to distinct clusters
of 4 – 6. Scales persistently covering the rhizome, peltate, 5 –70 by 0.5 –1 mm, appressed
(sometimes spreading), dark, shining with pale to brown margin and acumen, margin
ciliate especially when young. Fronds monomorphic; phyllopodia short, usually less
than 5 mm high, stipe 1–1.5 cm long, without dark coloration, with up to 1 mm long
glandular hairs and often small, appressed scales; lamina 13 – 30 by 1.2 – 3.3 cm, linear,
base narrowly cuneate to rounded, apex acuminate to caudate with cauda to 1.5 cm,
texture coriaceous; costa and veins on lower surface densely hairy with up to 1 mm long,
acicular hairs, costa without dark coloration, with copious, conspicuous, 3 – 4 mm long
pale to brown scales, upper surface more glabrous, mostly hairy on the costa only, with
similar hairs and with less copious scales. Sori in a single more or less irregular medial
row, separated from the costa by a 2 –7 mm wide sterile zone, indusium distinct, c. 1.5
mm wide, glabrous or glandular. Sporangial stalk with glands below the sporangium.
Spores with coarse confluent ridges, areolae with short pointed excrescences, perispore
hollow, with internal baculae, outer layer distinctly perforated.
Distribution — In Malesia: Borneo: Sarawak, Brunei, Kalimantan Timur.
Ecology — Terrestrial in montane forest, mainly on ridges and in summit vegetation,
1100 – 2200 m altitude.
Notes — 1. Creeping and rooting parts of the rhizome are absent in all collections
seen, but presumably present, as in O. neriiformis.
2. Much more coriaceous than O. neriiformis, and with copious large pale costal
scales and long hairs especially on lower surface. The sori are consistently medial, with
firm indusia that are often clearly glandular on their surface.
128 Flora Malesiana, Ser. II, Vol. 4 (2012)

2. Oleandra cumingii J.Sm.

Oleandra cumingii J.Sm., J. Bot. (Hooker) 3 (1841) 413; Copel., Polypod. Phil. Isl. (1905) 49; Fern
Fl. Philipp. 1 (1958) 184; Ching, Fl. Reipubl. Popularis Sin. 2 (1959) 324. — Type: Cuming 60 p.p.
(holo K; iso B, BM, SING, US*), Luzon.
Oleandra scandens Copel., Philipp. J. Sci. 46 (1931) 218; Fern Fl. Philipp. 1 (1958) 184. — Type:
Elmer 6513 (US*), Baguio.

Rhizome short- to long creeping, 3 – 8 mm thick, little branched and not forming ex-
tensive stands, in cross-section with or without scattered sclerified strands, sometimes
white waxy in the older parts; roots scattered, sometimes with unbranched aerial parts;
fronds scattered or more or less tufted. Scales persistently covering the rhizome, peltate,
4 –9 by 5 –1.5 mm, appressed, acumen with dark centre and lighter acumen and margin,
margin ciliate especially when young. Fronds monomorphic, phyllopodia (1–)3 –10 cm
high, stipe 2 –12 cm long, without dark coloration, glabrous or hairy with catenate to
acicular up to 2 mm long hairs, lamina to c. 40 by 2 – 4.5 cm, base narrowly cuneate
to truncate, apex acute to long-acuminate, texture thin-chartaceous, both surfaces and
margin with catenate or acicular hairs 0.2 –1 mm long, usually more densely on lower
surface, costa without dark coloration, on lower surface without or with few, pale to
dark scales. Sori close to or scattered up to 2 mm from the costa, indusium distinct, 1– 2
mm wide, densely hairy with short or long hairs. Sporangial stalk with glands below
the sporangium. Spores with broad or narrow confluent ridges, surface variably orna-
mented with small pustules to narrow spines, perispore hollow, with internal baculae,
outer layer not or finely perforated, sometimes fissured along the ridges.
Distribution — South China, Indochina (Laos, Thailand); in Malesia: Peninsular
Malaysia; Lesser Sunda Islands: Flores, Timor Leste; Philippines: Luzon.
Ecology — Terrestrial or on rocks, cliffs and roadsides in open forest, to c. 1200 m
altitude.
Note — Oleandra cumingii is a variable assemblage of fairly widely scattered forms,
in many characters intermediate between O. musifolia and the non-Malesian O. un­
dulata. From O. musifolia it differs in the elongated phyllopodia and the distinctly
tomentose indusia and lower surface of the lamina. The differences, however, are often
slight and bridged by some specimens with an intermediate character combination.

3. Oleandra musifolia Blume

Oleandra musifolia Blume, Enum. Pl. Javae (1828) 141 (‘Aspidium musaefolium’). — Oleandra musae­
folia C.Presl, Epimel. Bot. (1849) 42; Ching, Fl. Reipubl. Popularis Sin. 2 (1959) 321. — Oleandra
musifolia C.Chr., Index Filic. 466 (1906); Backer & Posth., Varenfl. Jav. (1939) 87; R.M.Tryon,
Rhodora 102 (2000) 434, f. 4. — Type: Blume s.n. (L), Java, Gedeh.
Aspidium lomatopus Kunze, Bot. Zeitung (Berlin) 11 (1848) 238. — Oleandra lomatopus C.Presl,
Epimel. Bot. (1849) 43. — Type: Zollinger s.n. (n.v.), Java.
Aspidium moritzii Kunze, Bot. Zeitung (Berlin) 11 (1848) 238; (1851) 348. — Oleandra moritzii
C.Presl, Epimel. Bot. (1849) 42. — Type: Zollinger 1306B (lecto L, L0317415), Java.

* Specimens seen only as on-line images, provided either directly through the databse of the holding
institute or via JSTOR, http://plants.jstor.org.
Hovenkamp & Ho — Oleandraceae 129

Oleandra geniculata Alderw., Bull. Jard. Bot. Buitenzorg 16 (1914) 23. — Type: Docters van Leeuwen
s.n. (BO?, n.v.), Java.
Oleandra benguetensis Copel., Philipp. J. Sci. 46 (1931) 217; Fern Fl. Philipp. 1 (1958) 183. — Type:
Elmer 6286 (US*), Baguio.

Rhizome creeping, 5 – 8 mm thick, often supported above the substrate by unbranched

stilt-like roots, dorsiventrally flattened, (strongly compressed, 4 – 6 mm wide when dry),
with up to 10 cm long, curved internodes (only occasionally straight and then often
much longer) terminating in a cluster of a few fronds, with an innovation just below
this cluster, lateral branches usually basal on the internodes, in opposite pairs; all parts
in cross-section without or with few sclerified strands, white waxy in the older parts;
roots scattered, with long unbranched aerial parts. Scales persistently covering the rhi-
zome, peltate, 5 –10 by 1–1.5 mm, appressed, with dark centre and lighter brown acu-
men and margin, margin ciliate especially when young and with sessile glands. Fronds
monomorphic, phyllopodia short, usually less than 5(–15) mm high, often hidden by
the scales, stipe 0.5 – 4 cm long, without dark coloration, with short, glandular hairs;
lamina to 60 by 4.2 cm, linear, base cuneate to truncate or more or less rounded, apex
acute to long-acuminate, texture thin-chartaceous, both surfaces with catenate, often
glandular hairs 0.2 – 0.5 mm long; costa without dark coloration, on lower surface with
inconspicuous, 1– 3 mm long brown scales. Sori mostly in a single regular row close
to the costa, sometimes more scattered over a 2 – 5 mm wide zone close to the costa or
at a distance of up to 3 mm, indusium distinct, 1.5 – 2 mm wide, glabrous or glandular,
sometimes setose. Sporangial stalk with glands below the sporangium. Spores with
coarse confluent ridges, areolae with short pointed excrescences, perispore hollow, with
internal baculae, outer layer not or hardly perforated.
Distribution — Southern India, Sri Lanka, South China, Thailand; in Malesia: Java;
Lesser Sunda Islands; Philippines: Luzon, Sulawesi; Australia: Queensland.
Ecology — Mostly terrestrial or on rocks, less often as low trunk epiphyte, in various
types of forest, often disturbed, up to c. 2000 m altitude.
Notes — 1. Variability: Density of hairs is variable, as is the distance of the sori to
the costa.
2. Oleandra musifolia is distinguished from O. cumingii mainly by the short phyl-
lopodia (long in O. cumingii). Incomplete collections are easily confused also with
O. neriiformis but can often be recognized by the flat, softer rhizome usually with-
out sclerenchyma strands (rhizome more rigid, rounded, with sclerenchyma strands in
O. neriiformis) and by the catenate hairs with capitate apex (more acicular, not capitate
in O. neriiformis). Distinguishing these two species on basis of juvenile material may
be difficult, and is often impossible, while it may not be clear from herbarium material
that the material is juvenile.

4. Oleandra neriiformis Cav.

Oleandra neriiformis Cav., Anales Hist. Nat. 2 (1799) 115 (‘neriformis’); Descr. Pl. 252 (1802); Backer
& Posth., Varenfl. Jav. (1939) 87; Copel., Fern Fl. Philipp. 1 (1958) 182; Brownlie, Pterid. Fl. Fiji
(1977) 156; R.M.Tryon, Rhodora 102 (2000) 430. — Aspidium neriiforme Sw., Syn. Fil. (1806)
42. — Type: Née s.n. (MA, n.v.), Mauban.
130 Flora Malesiana, Ser. II, Vol. 4 (2012)

Aspidium pistillare Sw., J. Bot. (Schrader) (1801) 30. — Oleandra pistillaris C.Chr., Index Filic. Suppl.
3 (1934) 132; Holttum, Flora of Malaya. II Ferns (1954) 386; X.C.Zhang, Ching Mem. Vol. (1999)
91. — Type: Unknown s.n. (S, n.v.), Java (teste Sw. 1806).
Ophiopteris verticillata Reinw., Syll. Pl. Nov. 2 (1825) 3. — Type: Reinwardt? s.n. (L), Java.
Aspidium bantamense Blume, Enum. Filic. 2 (1828) 141. — Aspidium micranthum Blume, Enum.
Filic. (1828) 141. — Oleandra bantamense Kunze, Bot. Zeitung (Berlin) 9 (1851) 349. — Oleandra
micrantha Kunze, Linnaea 9 (1851) 349. — Type: Kuhl & Van Hasselt s.n. (L), Java.
Aspidium neriiforme Sw. var. salaccens Blume, Enum. Pl. Javae (1828) add. et emend. — Aspidium
salaccense Blume, Enum. Filic. (1828) 140. — Oleandra neriiformis Cav. var. salaccensis Kunze,
Bot. Zeitung (Berlin) 9 (1851) 348. — Type: Blume s.n. (L), Java.
Blechnum colubrinum Blanco, Fl. Filip. (1837) 834. — Oleandra colubrina (Blanco) Copel., Polypod.
Phil. Isl. (1905) 48; Merr., Sp. Blancoan. (1918) 43; Copel., Fern Fl. Philipp. 1 (1958) 181. — Type:
Unknown.
Aspidium phyllarthron Kunze, Bot. Zeitung (Berlin) 6 (1848) 237. — Oleandra phyllarthron C.Presl,
Epimel. Bot. (1849) 42. — Type: Zollinger 1306 (L, L0317564), Java.
Oleandra mollis C.Presl, Epimel. Bot. (1849) 41; Fée, Gen. Fil. (1852) 304. — Type: Cuming 94 p.p.
(holo PRC, n.v.; iso BM, L, SING, US*), Luzon.
Oleandra hirtella Kunze, Farrnkräuter (1850) 70. — Oleandra neriiformis Cav. var. hirtella Hook.f.,
Sp. Fil. 4 (1862) 156. — Type: Miquel? s.n. (L?, not found), Java.
Oleandra neriiformis Cav. var. brachypus Hook.f., Sp. Fil. (1862) 156. — Type: Norris s.n. (K, n.v.),
Malay Archipelago.
Oleandra cumingii J.Sm. var. tahitense Hook.f., Sp. Fil. (1862) 159. — Type: Greville s.n. (K, n.v.),
Tahiti.
Oleandra ciliata Kuhn, Linnaea 36 (1869) 126. — Type: Cuming 48 (holo B), Aneiteum.
Oleandra cuspidata Baker, Malesia 3 (1886) 44. — Type: Beccari s.n. (K), New Guinea, Arfak.
Oleandra colubrina (Blanco) Copel. var. membranacea Copel., Philipp. J. Sci., Bot. 3 (1908) 32. —
Type: Copeland PPE57 (holo MICH; iso K, PNH, UC), Mt Maquiling.
Oleandra colubrina (Blanco) Copel. var. nitida Copel., Philipp. J. Sci., Bot. 3 (1908) 33. — Olean­
dra nitida Copel., Fern Fl. Philipp. 1 (1958) 181; Amoroso & Pava, Philipp. J. Sci. 120 (1991)
423. — Type: Copeland 1474 (lecto US*), Mt Apo.
Oleandra oblanceolata Copel., Philipp. J. Sci., Bot. 7C (1912) 64. — Type: Brooks 115 (MICH), Borneo.
Oleandra colubrina (Blanco) Copel. var. membranacea Brause, Bot. Jahrb. Syst. 56 (1921) 119. —
Type: Whitford 999 (B, n.v.), Mt Banajao.
Oleandra maquilingensis Copel., Philipp. J. Sci. 46 (1931) 217; M.G.Price, Philipp. Agric. 57 (1974)
42; P.M.Zamora & Co, Guide Philipp. Fl. Fauna (1986) 145; Amoroso & Pava, Philipp. J. Sci. 120
(1991) 423. — Type: Matthew s.n. (lecto MICH), Luzon.
Oleandra archboldii Copel., Philipp. J. Sci. 73 (1940) 346. — Type: Brass 13002 (n.v.), New Guinea.
Oleandra subdimorpha Copel., J. Arnold Arbor. 24 (1943) 441. — Type: Brass 6886 (GH, n.v.), New
Guinea.
Oleandra clemensiae Copel., Philipp. J. Sci. 81 (1952) 12; Fern Fl. Philipp. 1 (1958) 182. — Type:
Clemens 16494 (holo MICH; iso UC*), Philippines.
Oleandra herrei Copel., Philipp. J. Sci. 81 (1952) 12; Fern Fl. Philipp. 1 (1958) 182. — Type: Herre
s.n. (UC*), Philippines.
Oleandra malasianum S.R.Ghosh, J. Bombay Nat. Hist. Soc. 80 (1984) 630. — Type: Cantor-Wallich
2235 (CAL, n.v.), Penang.

Rhizome with main stems creeping or ascending, 3 – 8 mm thick, creeping parts

sparsely rooting, branches often in opposite pairs, ascending parts rootless, at base prop­
ped up by downwards directed branches, ultimately aerial, erect or pendent; branches

* See note p. 128.

Hovenkamp & Ho — Oleandraceae 131

single or in opposite pairs, mostly directly above a frond cluster, all parts in cross-
section with a peripheral sclerified sheath and scattered sclerified strands, white waxy
in the older parts, fronds on creeping parts few, scattered, on aerial parts in more or less
dense, often whorled clusters and branches. Scales persistently covering the rhizome,
peltate, 4 – 6.5 by 1–1.5 mm, appressed to squarrose, with dark centre and lighter margin
and acumen, margin ciliate. Fronds monomorphic or weakly dimorphic, phyllopodia
very short or up to 15 mm long, stipe very short or up to 3.5 cm, without dark colora-
tion; fertile lamina 12 – 43 by 0.5 – 4.5 cm, base very gradually narrowed to narrowly
truncate, then often somewhat lyrate, apex acuminate or to c. 2 cm caudate; sterile, if
present, usually slightly shorter and wider, to 36 by 5.5 cm; texture thin-chartaceous,
costa and lamina on lower surface without dark coloration, glabrous or with up to 2 mm
long hairs, costa often with up to 2 mm pale to dark narrow scales. Sori in a single row
close to the costa, or more scattered over a 2 – 5 mm wide zone close to or at a distance
of up to 4 mm from the costa, indusium inconspicuous to distinct, to c. 1.5 mm wide,
glabrous to hairy. Sporangial stalk with glands below the sporangium. Spores with
coarse confluent ridges, surface pustulose or with pointed excrescences, outer layer
variably perforated. — Fig. 1.
Distribution  —  Himalayas (India: Assam, Bengal; China: Xizang), Indochina, through-
out Malesia; Pacific Islands (Fiji, Samoa).
Ecology — Terrestrial or epiphytic, in various types of forests, in open places, often
making up a significant part of summit or ridge scrub. Sea level to 2200 m altitude.

Variability
With its wide-creeping and persistent rhizome, O. neriiformis may form extensive and
probably long-lived stands, which, when collected a number of times over a long period,
may give the impression of the presence of a locally abundant species with highly con-
stant and distinct combination of characters. I expect this is at least partly the basis for
the multitude of local species that have been described, and that I all include in O. nerii­
formis. Another reason may be the presence of juvenile plants, in which the rhizome is
not characteristically developed, and which may have much more softly hairy fronds
than well-developed plants, blurring the distinctions to O. musifolia and O. cumingii.
The following characters or character complexes in particular are variable:
1. Place of the stipe articulation. The phyllopodium may be distinctly longer than the
very short stipe, or a distinctly elongated stipe may be present equal to or longer than
the phyllopodium.
2. Length and density of lamina hairs. Although the presence or length of lamina hairs
is usually highly variable, some forms have constantly and distinctly longer hairs.
3. Location of soral zone. Sori may be located in a narrow zone close to the costa, or in
a more irregular zone at some distance from the costa, thus always leaving a distinct
sterile zone between costa and sori.
4. Indusium. The presence of an indusium is rarely constant over an area. It may vary
from distinct and often firm to inconspicuous (then often hairy) or absent.
5. Costal scales. Some forms have uniformly pale and flat costal scales, some almost
uniformly narrow, dark scales, other forms have more variation in this character.
132 Flora Malesiana, Ser. II, Vol. 4 (2012)

g
i 1 mm 1 mm

h
1 mm

j
1 mm

a
1 mm

b c d e f
1 cm
1 mm
Fig. 1. Oleandra neriiformis Cav. a, b. Aerial erect rhizome with whorls of phyllopodia; c – e. fertile
fronds; g. lyrate lamina base; h. rounded lamina base; i. medial sori, without conspicuous indusia;
j. costal sori, with conspicuous indusia (a: Chew, Corner & Stainton 298; b, c, l: Chew 942; d: Copeland
s.n., 29 Jan. 1933; e, g, i: Brass 23016; f: Croft 66; h: Van Balgooy 5223; all L.) Drawing by Anita
Walsmit Sachs.
Hovenkamp & Ho — Oleandraceae 133

Geographic variation and local forms

Over most of the distribution area, two forms can often easily be distinguished locally,
on basis of the relative length of phyllopodium and stipe. Stipitate forms have short
phyllopodia, elongated stipes (thus the articulation is positioned at the base of the phyl-
lopodium/stipe), the lamina gradually narrowed towards the base, and sori relatively
close to the costa. The other form is characterized by longer phyllopodia, stipes short
or absent (thus the lamina appearing sessile with regard to the articulation), usually a
truncate lamina base (although the lamina directly above the base may be strongly nar-
rowed, the base is still suddenly contracted, and often somewhat lyrate) that is clearly
set off against the stipe, and sori in a more variable position, in some cases almost at
the margin. However, other characters, such as indument, or indusium are indepently
variable and often show similar states in the two forms in the same area.

Java, Sumatra
On Java and Sumatra, there is no clear distinction between stipitate and sessile forms, as
both stipe and phyllopodium length are strongly variable and extremes are not sharply
separated. In Backer & Posthumus (Varenflora voor Java, 1939), all are taken together
as O. neriiformis.

Peninsular Malaysia, Southern Thailand

In collections from the Malay Peninsula the difference between stipitate and sessile
forms is associated with differences in hairiness of the lamina and position of the sori.
Holttum (Rev. Flora Malaya II. Ferns, 1968) also distinguishes these two forms, on
basis of the same characters, but notes that they are not sharply distinct, nor ecological­
ly sharply separated, although he cites a difference in altitudinal preference. The scant
label data I have seen indicate no differences in preference for epiphytism vs terrestrial,
or for altitude.

Borneo
On Borneo, the two forms also differ in hairiness of lamina, but not in the position of
the sori, which are usually more or less closely costal. Here, the stipitate form is almost
exclusively reported as epiphyte, the other form as terrestrial. Both forms tend to have
narrower, darker costa-scales than in other areas. Completely glabrous forms such as
are most common on Java and Sumatra are not found on Borneo. The sessile form has
been described as O. oblanceolata Copel.

Philippines
On the Philippines, distinctly stipitate forms represent a small minority of all collec-
tions. The two forms here do not show any difference in degree of hairiness and position
of the sori, but share a distinctly hairy lamina and more copious, pale, flat rachis-scales
than the forms in other areas.
Copeland (Fern Fl. Philipp. 1958) distinguishes O. neriiformis from the short-stipi­
tate form, and within the latter a number of species, based on details of indument:
O. herrei, with paleate costa, O. colubrina, with setose costa and hairy lamina, O. nitida,
134 Flora Malesiana, Ser. II, Vol. 4 (2012)

with setose costa and glabrescent lamina. We find that although the density of costal
scales varies strongly (it seems to be negatively and weakly correlated with the density
of setae), scales can be found on all specimens, and the density of hairs on the lamina
varies strongly. We see no basis on which these characters could lead to the distinction
of clear groups.

Celebes, Moluccas
South of the Philippines, two forms co-occur on Celebes and the Moluccas, while the
stipitate form extends to the Solomon Islands and Vanuatu. Both forms here share rather
indistinct indusia, which may be shortly setose.
Kato (J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 14, 4 (1989)), distinguishes the speci-
mens from Ceram with very small, setose indusia as O. cuspidata, but we find that this
represents only the extreme state of variability.

New Guinea and surrounding islands

The stipitate form that extends eastwards from Celebes co-occurs, on the main island
of New Guinea, with a sessile form that is often distinctly dimorphic and has sori often
quite distant from the costa.

5. Oleandra sibbaldii Grev.

Oleandra sibbaldii Grev., Ann. Mag. Nat. Hist. 1 (1848) 327; Copel., Fern Fl. Philipp. 1 (1958) 183;
Brownlie, Pterid. Fl. Fiji (1977) 157; R.M.Tryon, Rhodora 102 (2000) 436, f. 7. — Oleandra cum­
ingii J.Sm. var. sibbaldii Baker, Syn. Fil. (1867) 303. — Type: Sibbald s.n. (E, barcode E00417634,
n.v.), Tahiti.
Oleandra tricholepis Kunze, Bot. Zeitung (Berlin) 9 (1851) 349. — Type: Hupe s.n. (LZ, probably
destroyed), Borneo.
Oleandra gracilis Copel., Univ. Calif. Publ. Bot. 12 (1931) 397, t. 52b; Philipp. J. Sci. 73 (1940) 347.
— Type: Keysser 74 (UC), New Guinea.
Oleandra crassipes Copel., Philipp. J. Sci. 73 (1940) 347, t. 2. — Type: Brass 12109 (holo UC; iso
BO, L), New Guinea.

Rhizome long-creeping or pendulous, sparsely branching, 1.5 – 4.5 mm thick, in

cross-section without or with few scattered sclerified strands, very strongly white waxy,
fronds scattered, roots with distinct unbranched parts. Scales deciduous, exposing the
rhizome in older parts, peltate, (3 –)5 –15(–18) by (0.3 –)0.4 – 0.9(–1.2) mm, usually
widest above the attachment, squarrose, reddish brown, margin entire or more or less
densely set with sessile glands, acumen attenuated, long filiform apex. Fronds mono-
morphic; phyllopodia distinct, (0.3 –)0.8 – 4(– 5.7) cm high, stipe (0.3 –)0.5 – 3.5(– 4.5)
cm long, often with dark coloration on abaxial side; lamina to (4.5 –)15 – 40(– 58) by
1– 4(– 6) cm, widest in middle part, base attenuate to cuneate, sometimes rounded,
rarely truncate, sometimes asymmetric, apex acuminate or up to 3 cm caudate, texture
membranous to coriaceous, both sides sparsely to densely set with catenate hairs to
c. 0.5 mm long; costa on lower surface often with dark-coloration, on both surfaces
with scales, scales on lower surface often abundant, to 6(–11) by 1(–1.2) mm, pale to
dark brown, on upper surface scarce, inconspicuous. Sori inframedial, leaving a distinct
1– 4 mm wide sterile zone between costa and soral zone, sometimes as much as 12 mm
Hovenkamp & Ho — Oleandraceae 135

from costa, indusium firm, to 1 mm wide, hairy. Sporangial stalk with glands below
the sporangium. Spores with an irregular mesh-like network of up to 10 μm high folds,
finely papillose with spinules up to c. 4 by 1 μm, perispore baculate, outer layer much
perforated.
Distribution — Eastern Malesia to Vanuatu, Fiji, Western Samoa, Tahiti. In Malesia:
Borneo: Sabah, Sarawak; Philippines: Mindanao; Sulawesi; Moluccas; New Guinea.
Ecology — Epiphytic, epilithic, or less commonly terrestrial (> 1500 m), climbing
or sprawling among bryophytes and other epiphytes, or pendulous from mossy tree
branches; commonly collected from mossy forest. Altitude to 600 m (Marquesas and
Tahiti) or 1000 – 3000 m above sea level.
Note — The dark colour on the abaxial surface of the costa is often very conspicuous,
extending on the stipe, thus rendering the stipe conspicuously bicolorous.

6. Oleandra vulpina C.Chr.

Oleandra vulpina C.Chr., Dansk Bot. Ark. 9 (1937) 68. — Type: Ledermann 7652 (BM), New Guinea.

Rhizome long-creeping, c. 3 mm thick, sparsely branching, not glaucous, roots with

unbranched parts; in cross-section with weakly developed sclerified shealth and few
scattered sclerenchyma strands, fronds scattered, 3 – 6 cm distant. Scales scattered, not
covering the rhizome, peltate, to 5 by 0.5 mm, appressed at the base, with a narrow
squarrose acumen, dark brown near attachment, lighter towards margin, margin densely
set with glands and multicellular hairs terminating in a gland. Fronds monomorphic,
phyllopodia 6 –7 mm long, with scales as the rhizome but less dense and short fine glan-
dular hairs; stipe 2 – 3 mm long, without dark coloration on abaxial side, bearing short
fine glandular hairs; lamina linear-lanceolate, 20 –17.5 by 3 – 4 cm wide, base cuneate,
apex short caudate, tips up to 1 cm long, margin undulate, weakly cartilaginous, texture
papyraceous, all parts with to 0.5 mm long catenate glandular hairs, or with longer, to
1.5 mm, acicular hairs; costa abaxially without dark coloration, with hairs like the stipe
and with small scales; veins terminating in a weakly developed hydathode before the
margin. Sporangial stalk with glands below the sporangium. Sori in an irregular row
2.5 – 6 mm from the costa, indusium round-reniform, c. 0.5 mm across, fugacious at
very early stage. Spores not seen.
Distribution — Malesia: New Guinea.
Ecology — Scandent on trunk of Sago palm in garden, or in forest, at 975 m altitude.
Vernacular name — Taingelem (Wapi language, Miwaute).
Note — Distinct from O. sibbaldii in the rhizome and costa scales. Rhizome scales
are darker in colour with pale-coloured margin, apices long subulate, margin strongly
ciliated with glandular hairs. In addition, the rhizome of O. vulpina is not glaucous. The
indusia are very small and shrivel at a very young stage but are distinct when present
in the numerous setose hairs.

7. Oleandra werneri Rosenst.

Oleandra werneri Rosenst., Feddes Repert. Spec. Nov. Regni Veg. 5 (1908) 40; Copel., Philipp. J. Sci.
73 (1940) 347; R.M.Tryon, Rhodora 102 (2000) 433, f. 3. — Type: Werner 12 (lecto L ‘Rosenstock
28’, here selected), New Guinea.
136 Flora Malesiana, Ser. II, Vol. 4 (2012)

Oleandra dimorpha Copel., Philipp. J. Sci. 60 (1936) 111. — Type: Brass 2916 (holo MICH), San
Christoval.

Rhizome with main stems creeping, scrambling or pendent, 2 – 3 mm thick, sparsely

rooting, mostly terete when dry; all parts in cross-section with a peripheral sclerified
sheath and scattered sclerified strands, white waxy in the older parts, fronds scattered
on creeping parts, fronds more closely together but not densely clustered on aerial parts.
Scales covering the rhizome, peltate, 3 – 4 by 0.5 –1 mm, somewhat squarrose, with dark
centre and lighter margin and acumen, margin ciliate especially when young. Fronds
strongly dimorphic, phyllopodia short, usually less than 5 mm high, stipe 0.5 – 2.5 cm,
without dark coloration, especially upwards with up to 2 mm long hairs; fertile lamina
27– 56 by 0.5 –1(–1.7) cm, base and apex narrow, sterile 17– 30 by 2.2 – 5.7 cm, base
mostly cuneate, apex distinctly 2 – 3.5 cm caudate; texture chartaceous, costa and lamina
on lower surface glabrous or with up to 2 mm long hairs, costa without dark coloration,
like the stipe with up to 2 mm long brown scales. Sori in a single row on both sides of
the costa, indusium firm, 1– 3 mm wide, glabrous. Sporangial stalk with glands below
the sporangium. Spores with coarse confluent ridges, areolae with short pointed excres-
cences, perispore hollow, with internal baculae, outer layer not or hardly perforated.
Distribution — In Malesia: Moluccas, New Guinea; Vanuatu.
Ecology — Commonly epiphytic, on trunks or in crowns, less often terrestrial or
on rocks, erect, scrambling or pendent, in various types of forest, most frequently in
montane or mossy forest, on ridges, up to c. 2000 m altitude.
Notes — 1. As with O. neriiformis, rhizome morphology is probably more compli-
cated than can be inferred from the mostly aerial unbranching parts making up most of
the collected material.
2. Hairiness is very variable, and while there is no sharp distinction between hairy
and glabrous forms, it is noteworthy that hairy forms tend to occur at especially the
western extreme of the distribution area, with less hairy forms near the eastern extreme,
and glabrous forms mostly on the mainland of New Guinea.