Oleandra neriiformis

Hovenkamp, Peter H. & Ho, Boon-Chuan, 2012, A revision of the fern genus Oleandra (Oleandraceae) in Asia, PhytoKeys 11, pp. 1-37 : 11-16

4. Oleandra neriiformis Map 3 fig. 11 a-c, g-m 12

Oleandra neriiformis Cav., Anales Hist. Nat. 2: 115. 1799. (as " neriformis "); Descr. Pl. (Cavanilles): 252. 1802. C.Presl, Tent. Pterid.: 78. 1836. (as " neriifolia"); C.Presl, Epimel. Bot.: 42. 1851. Fée, Mém. Foug., 5. Gen. Filic.: 304. 1852. Hook., Sp. Fil.: 156. 1862. Copel., Polypod. Phil. Isl.: 49. 1905. Backer & Posth., Varenfl. Jav.: 87. 1939. Copel., Philipp. J. Sci. 73: 346. 1940. C.Chr., Bull. Bernice P. Bishop Mus. 177 45. 1943. Copel., Fern Flora of the Philippines: 182. 1958. Brownlie, The Pteridophyte Flora of Fiji: 156. 1977. M.Kato, J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 14: 240. 1989. R.M.Tryon, Rhodora 102: 430. 2001. Aspidium neriiforme Sw., Syn. Fil. (Swartz) 42. 1806. Willd., Sp. Pl., ed. 4 [Willdenow] 5: 212. 1810. Blume, Enum. Pl. Javae: 140. 1828. Gariletti, Fontqueria 38: 40. 1993. Type: PHILIPPINES. Mauban: Née s.n. (holotype: MA 476029, teste Gariletti, not seen).

Aspidium pistillare Sw., J. Bot. (Schrader) 1800: 30. 1801. Oleandra pistillaris C.Chr., Index Filic., Suppl. Tertium pro Annis 1917-1933: 132. 1934. Holttum, Rev. Fl. Mal. 2: 386. 1954. X.C.Zhang, Ching Mem. Vol.: 91. 1999. Type: INDONESIA. Java: Unknown s.n. (holotype S, not seen) (teste Sw. 1806).

Ophiopteris verticillata Reinw., Syll. Pl. Nov. 2: 3. 1825. Type: INDONESIA. Java: Reinwardt (?) s.n.(L).

Aspidium bantamense Blume, Enum. Pl. Javae: 141. 1828. Oleandra bantamense Kunze, Bot. Zeitung (Berlin) 9: 349. 1851. Type: INDONESIA. Java: Bantam, anon. (Kuhl & van Hasselt?) s.n.(Holotype: L).

Aspidium micranthum Blume, Enum. Pl. Javae: 141. 1828. Oleandra micrantha Kunze, Bot. Zeitung (Berlin) 9: 349. 1851. Type: INDONESIA. Java, Salak.: anon. (Kuhl & van Hasselt?) s.n.(holotype: L).

Aspidium salaccense Blume, Enum. Pl. Javae: 140. 1828. Aspidium neriiforme var. salaccense Blume, Enum. Pl. Javae: Add. et emend. 1828. Oleandra neriiformis var. salaccensis Kunze, Bot. Zeitung (Berlin) 9: 348. 1851. Type: INDONESIA. Java: Blume s.n. (holotype: L).

Blechnum colubrinum Blanco, Fl. Filip. [F.M. Blanco]: 834. 1837. Oleandra colubrina Copel., Polypod. Phil. Isl.: 48. 1905. Copel., Fragm. Fl. Philipp. 3 179. 1905. Merrill, Sp. Blancoan.: 43. 1918. Copel., Fern Flora of the Philippines: 181. 1958. M.Kato, J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 14: 240. 1989. Type: PHILIPPINES. Unknown.

Aspidium phyllarthron Kunze, Bot. Zeitung (Berlin) 6: 237. 1848. Oleandra phyllarthron C.Presl, Epimel. Bot.: 42. 1851. Kunze, Bot. Zeitung (Berlin) 9: 349. 1851. Type: INDONESIA. Java: Zollinger 1306 (lectotype: L 0317564, here selected) (see discussion).

Oleandra hirtella Kunze, Farnkräuter: 70, pl. 129. 1847. Fée, Mém. Foug., 5. Gen. Filic.: 304. 1852. Oleandra neriiformis var. hirtella Hook., Sp. Fil.: 156. 1862.Type: INDONESIA. Java: Miquel? s.n. (holotype L?, not found).

Oleandra mollis C.Presl, Epimel. Bot.: 41. 1851. Fée, Mém. Foug., 5. Gen. Filic.: 304. 1852. Type: PHILIPPINES. Luzon: Cuming 94 p.p. (holotype: PRC, not seen; isotypes: BM, L, SING, US*).

Oleandra neriiformis var. brachypus Hook., Sp. Fil.: 156. 1862. Type: UNKNOWN. Malay Archipelago: Norris s.n. (holotype: K, not seen).

Oleandra cumingii var. tahitense Hook., Sp. Fil.: 159. 1862. Type: FRENCH POLYNESIA. Tahiti: Greville s.n. (holotype: K, not seen).

Oleandra ciliata Kuhn, Linnaea 36: 126. 1869. Type: VANUATU. Aneiteum: Cuming 48 (holotype: B).

Oleandra cuspidata Baker in Becc., Malesia 3: 44. 1886. Copel., Philipp. J. Sci. 73: 346. 1940. M.Kato, J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 14: 239. 1989. Type: INDONESIA. New Guinea: Arfak, Beccari s.n. (holotype: K).

Oleandra colubrina var. nitida Copel., Philipp. J. Sci., C 3: 33. 1908. Oleandra nitida Copel., Fern Flora of the Philippines: 181. 1958. Amoroso & Pava, Philipp. J. Sci. 120: 423, 437. 1991. Type: PHILIPPINES. Mindanao: Mt. Apo, Copeland 1474(lectotype: US*, here selected).

Oleandra colubrina var. membranacea Copel., Philipp. J. Sci., C 3: 32. 1908. Type: PHILIPPINES. Luzon: Mt. Maquiling, Copeland PPE57 (holotype MICH; isotypes K, PNH, UC).

Oleandra oblanceolata Copel., Philipp. J. Sci., C 7: 64. 1912. Type: MALAYSIA. Sarawak: Bungo Range, Brooks 115(holotype: MICH).

Oleandra samoensis Gand., Bull. Soc. Bot. France 66: 306. 1919. Type. SAMOA. Upolu: Reinecke s.n. (not seen).

Oleandra colubrina var. membranacea Brause, Bot. Jahrb. Syst. 56: 119. 1921. Type: PHILIPPINES. Luzon: Mt. Banajao, Whitford 999 (holotype: B, not seen).

Oleandra parksii Copel., Bull. Bernice P. Bishop Mus. 59: 86. 1929. Type: FRENCH POLYNESIA. Fiji: Parks 20759(holotype: BISH? not seen; isotypes: BM*, MICH, US*).

Oleandra platybasis Copel., Bull. Bernice P. Bishop Mus. 59 86. 1929. Type: FRENCH POLYNESIA. Fiji: Gillespie 3249 (holotype: BISH? not seen; isotypes: MICH, NY*, UC*).

Oleandra angusta Copel., J. Arnold Arbor. 12 48. 1931. Type: SOLOMON ISLANDS. Vanikoro: Kajewski 5371 (holotype: A? not seen; isotypes: US*; UC*).

Oleandra maquilingensis Copel., Philipp. J. Sci. 46: 217. 1931. M.G.Price, Philipp. Agric. 57: 42. 1974. Zamora & Co, Guide to Philippine flora and fauna 2: 145. 1988. Amoroso & Pava, Philipp. J. Sci. 120: 423-437. 1991. Type. PHILIPPINES. Luzon: Matthew s.n.(lectotype: MICH 1210440, here selected, see discussion).

Oleandra archboldii Copel., Philipp. J. Sci. 73: 346. 1940. Type: PAPUA NEW GUINEA. Brass 13002 (holotype: MICH*).

Oleandra subdimorpha Copel., J. Arnold Arbor. 24: 441. 1943. Type: PAPUA NEW GUINEA. Brass 6886 (holotype: GH, not seen, isotypes: BM*, MICH*).

Oleandra christopherseni C. Chr, Bull. Bernice P. Bishop Mus. 177 47. 1943. Type: SAMOA. Christophersen 126 (holotype: BISH; isotype: BO). Oleandra clemensiae Copel., Philipp. J. Sci. 81 12. 1952. Copel., Fern Flora of the Philippines: 182. 1958. Type: PHILIPPINES. Clemens 16494 (holotype: MICH; isotype: UC*).

Oleandra herrei Copel., Philipp. J. Sci. 81 12. 1952. Copel., Fern Flora of the Philippines: 182. 1958. Type: PHILIPPINES. Herre s.n.(holotype UC*).

Oleandra malasianum Ghosh, J. Bombay Nat. Hist. Soc. 80: 630. 1984. Type. MALAYSIA. Penang:: Cantor, Wallich 2235 (CAL, not seen, ill. in Ghosh 1984).

Description.

Rhizome with main stems creeping or ascending, 3-8 mm thick, white waxy in the older parts, creeping parts sparsely rooting, branches often in opposite pairs, ascending parts rootless, at base propped up by downwards directed branches, ultimately aerial, erect or pendent; branches 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, phyllopodia on creeping parts few, scattered, on aerial parts in more or less dense, often whorled clusters and branches, short to 15 mm long. Scales persistently covering the rhizome, peltate, 4-6.5 × 1-1.5 mm, appressed to squarrose, with dark center and lighter margin and acumen, margin ciliate. Fronds monomorphic or weakly dimorphic, stipe short to 3.5 cm long, without dark colouration; fertile lamina 12-43 × 0.5-4.5 cm, base 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 × 5.5 cm; texture thin-chartaceous, costa and lamina on lower surface without dark colouration, 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.

Distribution.

India (Himalayas), China (Xizang), Malesian archipelago to Australia, 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.

Discussion.

The epithet neriformis published by Cavanilles has to be corrected to " neriiformis " (ICBN 60.8). The epithet neriifolia used by Presl is either a mistake to be corrected or a superfluous nom. nov. and should not be used.

Oleandra neriiformis does not occur in Australia. The reference in Bell (1998) to Oleandra neriiformis refers indeed to Oleandra musifolia as suggested.

Oleandra maquilingensis is based on two sterile specimens that are considered to represent juvenile plants by Price (1974). Price selected, but did not publish, a lectotype from among the two, and we here follow that lectotypification. The identification of these sterile specimens with Oleandra neriiformis rather than Oleandra cumingii is somewhat conjectural, as is the identification of Blechnum colubrinum Blanco, for which no specimens at all are available.

Aspidium phyllarthron is one of the two species distinguished by Kunze (1848) among the specimens distributed as Zollinger 1306. In addition, Kunze cited Zollinger 1957. We have not found any specimens of Zollinger 1957, and from the several specimens that have been distributed as Zollinger 1306, we have selected one that fits the description of Aspidium phyllarthron and has a label “1306=1957”. Another specimen, labeled " Zollinger 1306 a, Aspidium phyllarthron " (L 0317412), does not fit the description and is Oleandra musifolia .

Variability.

With its wide-creeping and persistent rhizome, Oleandra neriiformis may form extensive and probably long-lived stands, which, especially when it is collected a number of times over a long period, may give the impression of the presence of a locally abundant species with a highly constant and distinct combination of characters. We expect this is at least partly the basis for the multitude of local species that have been described, and that we all include in Oleandra neriiformis . Another problem is posed by the occurrence 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 Oleandra musifolia and Oleandra cumingii .

The following characters or character complexes, some of which have been used to distinguish species, are variable in particular:

1 Place of the stipe articulation. The phyllopodium may be distinctly longer than the very short stipe ( fig. 12 k, n ), or a distinctly elongated stipe may be present equal to or longer than the phyllopodium ( fig. 12 a, d )

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 ( fig. 12 b, n ), or in a more irregular zone at some distance from the costa ( fig. 11 b, m ).

4 Indusium. The presence of an indusium is rarely constant over an area. It may vary from distinct and often firm ( fig. 11 h , 12 b ) to inconspicuous (then often hairy) or absent ( fig. 11 a, k ).

5 Costal scales: Some forms have uniformly pale and flat costal scales, some have almost uniformly narrow, dark scales, and there are forms that vary in this character.

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 phyllopodium/stipe), the lamina gradually narrowed towards the base, and sori relatively close to the costa ( fig. 12 k-m ). This corresponds to the type of Oleandra neriiformis . The other form is characterized by longer phyllopodia, stipes short or absent (thus the lamina appearing sessile with regard to the articulation, fig. 2 b ), usually a truncate lamina base (although the lamina directly above the base may be strongly narrowed, the base is still suddenly contracted, and often somewhat lyrate, fig. 2 c ) that is clearly set off against the stipe, and sori in a more variable position, in some cases almost at the margin ( fig. 2b ). Other characters, such as indument, or indusium are independently variable and often vary in a similar way across the two forms where they co-occur, thus giving rise to different characteristic character combination in different parts of the distribution area.

Continental Asia. The few collections from continental Asia do not allow for an evaluation of the variability.

Java, Sumatra. On Java and Sumatra, there is no distinction between stipitate and sessile forms, as both stipe and phyllopodium lengths are strongly variable and extremes are not sharply separated. In Backer and Posthumus (1939), all are taken together as Oleandra neriiformis . Description (see also fig. 12 h-j ): Phyllopodia 2-6 mm, stipes 3-10 mm, lamina base narrowed, never lyrate, lamina variably hairy (mostly glabrous), costal scales usually few, medium dark; sori costal or at short distance from the costa, indusia distinct to firm, glabrous.

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 (1968b) also distinguishes these two forms, on basis of the same characters, but notes that that they are not sharply distinct, nor ecologically sharply separated, although he cites a difference in elevational specificity. The scant label data indicate no differences in specificity for epiphytism vs terrestrial, or for elevation. Stipitate form description: Phyllopodia very short, stipes elongated, c. 5-10 mm long, lamina glabrous, occasionally hairy, margin glabrous or very nearly so, sori subcostal in an irregular row. Sessile form description (see also fig. 12 k-n ): Phyllopodia elongated, 1-6 mm long, stipes mostly very short, sometimes to 3 mm long, lamina hairy, sori strictly costal (rarely to 1 mm from costa).

Borneo. On Borneo, the two forms also differ in hairiness of lamina, but not in the position of the sori, which is 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 Oleandra oblanceolata Copel. Stipitate form description: Phyllopodia up to 6 mm long, stipe 7-25 mm, lamina at base gradually narrowed, usually hairy with relatively long hairs (rarely glabrous), costal scales more or less frequent, mostly brown. Almost exclusively reported as epiphyte. Sessile form description (see also fig. 11 g-j ): Phyllopodia 2-8 mm long, stipes at most 1 mm, lamina at base truncate, often ± lyrate, lamina mostly glabrous, sometimes short-hairy, costal scales not frequent, dark, narrow. Mostly reported as terrestrial.

Philippines. On the Philippines, distinctly stipitate forms represent a small minority of all collections (e.g., Cuming 94, Soejarto 8874, PNH 3862, 8710), but include the type of Oleandra neriiformis ( Christensen 1937). 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 (1958) distinguishes Oleandra neriiformis from the short-stipitate form, and within the latter a number of species, based on details of indument: Oleandra herrei , with paleate costa, Oleandra colubrina , with setose costa and lamina, Oleandra nitida , 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.

Stipitate form description: Phyllopodia to 2 mm, stipes to c. 7 mm, lamina and margin hairy with highly variable density, costa mostly with many pale scales, sori not closely costal to medial or submarginal, indusia glabrous, often small, indistinct. Sessile form description ( fig. 11 k-m ): Phyllopodia 5-15 mm, stipes short, up to 1 mm long, otherwise similar.

Celebes, Moluccas. In eastern Malesia 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 have indusia that are frequently shortly setose.

Stipitate form description: Phyllopodia 1-5 mm, stipes 8-25 mm, lamina base gradually narrowed, costal scales pale except near base of lamina, lamina setose, lamina hairs relatively long, margin often distinctly fimbriate with hairs shorter or equal to those on lamina, sori costal, indusia firm, with wide sinus, usually glabrous.

Sessile form description: Phyllopodia 5-15 mm, stipes very short to occasionally 3 mm long, lamina base narrowed to ultimately cuneate, not distinctly lyrate, lamina indument often long, conspicuous on all veins, margin often distinctly fimbriate with hairs similar to these on the lamina, costal scales few or absent, dark, sori narrowly costal, indusium distinct and persistent but not firm, often with narrow sinus, sometimes setose.

Kato (1989) distinguishes the specimens from Ceram with a very small, setose indusium as Oleandra cuspidata , but this represents only the extreme state of variability.

Fiji, Samoa. More eastwards in the Pacific Islands, there is no variability in the location of the articulation. All specimens from this area have elongated stipes, and can collectively be distinguished from the forms in other areas by the distinctly more lax clusters of fronds on the aerial stems ( fig. 12 a ), with the fronds mostly hardly clustered at all (a character in which they resemble Oleandra pilosa Hooker, from Tropical America). Regional differences show up mainly in the indument of the fronds. On Samoa, the lamina is less densely hairy than on Fiji, and the hairs on the lamina, when present, are distinctly shorter than those on the margin. Costa scales also differ, and are distinctly darker on Samoa than on Fiji, while sori are somewhat less strictly costal on Samoa.

Fiji form description (see also fig. 12 a-d ): Phyllopodia 1-9 mm, stipes 5-35 mm, lamina base gradually narrowed, costal scales pale, lamina setose, lamina hairs 1-2 mm long, margin often distinctly fimbriate, hairs on margin shorter or at most equal to those on lamina, sori costal, indusia distinct, glabrous or setose,

Samoa form description: Phyllopodia 1-7 mm, stipes 2-28 mm, lamina base gradually narrowed, costal scales brown to dark, lamina glabrous or setose, with hairs to 0.5 mm long on the lamina, 1-2 mm long on the margin, sori costal or subcostal leaving a sterile zone of 0.5-3 mm wide, indusia distinct, glabrous or setose.

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.

Stipitate form description (see also fig. 12 e-g ): Phyllopodia to 4 mm, stipes 5-25 mm, lamina base gradually narrowed, costal scales pale except near base of lamina, lamina setose, with hairs 0.5-1.5 mm long, margin glabrous, sori costal or subcostal leaving a sterile zone of 0.5-2.0 mm wide, indusia firm, with wide sinus, usually glabrous.

Sessile form description (see also fig. 11 a-c ): Phyllopodia to 4 mm, stipes very short or absent, articulation directly below the base of the lamina, fronds slightly but usually distinctly dimorphic, lamina narrowed to a truncate or somewhat lyrate base, costal scales mostly brown to dark, lamina glabrous or sometimes short setose, with hairs to 0.5 mm long, margin usually with a few scattered pale, acicular hairs especially near the base, sori medial or submarginal leaving a sterile zone of 0.5-7 mm wide, indusia small and inconspicuous in older sori, occasionally more distinct, often fringed with pale acicular hairs.

Figures

Map 3. Distribution of Oleandra neriiformis.

Figure 11. Oleandra neriiformis (a-c, g-m), Oleandra coriacea (d-f). a middle part of lamina, medial sori with indistinct indusia b entire lamina c lyrate lamina base with stipe articulation immediately below lamina base: Brass 2301 6 (New Guinea) d middle part of lamina, with conspicuous scales on midrib and sori with persistent indusia e entire lamina f lamina base with elongated stipe: Yahud et al SAR 88396 (Borneo) g entire lamina with costal sori h middle part of lamina, sori costal with persistent indusia i rounded lamina base with short stipe j whorl of short phyllopodia on aerial stem: Chew, Corner & Stainton 298 (Borneo) k middle part of lamina sori with inconspicuous indusium l rounded lamina base with short stipe m lamina: Copeland s. n. 29 jan 1933 (Philippines)., All views of lamina showing abaxial surface; all specimens L.

Figure 12. Oleandra neriiformis. a scattered phyllopodia on aerial stem b middle part of lamina with very closely costal sori and conspicuous indusia c lamina d lamina base with long stipe: A. C. Smith 6104 (Fiji) e lamina f lyrate lamina base with long stipe g middle part of lamina, sori costal with conspicuous indusia: Croft 66 (New Guinea) h middle part of lamina, sori costal with conspicuous indusia i lamina j cuneate lamina base with distinct stipe: Van Balgooy 5223 (Java) k irregularly whorled phyllopodia on aerial stem l middle part of lamina with very closely costal sori and conspicuous indusia m narrowed lamina base with articulation close to the lamina base n lamina: Chew W-L 94 2 (Peninsular Malaysia). All views of lamina showing abaxial surface; all specimens L.

Figures 1 - 8. 1 Oleandra cumingii, perispore with broad folds, low warty ornamentation, not perforated. scale bar 10 µm. Schmutz 6086 (L) 2 Oleandra cumingii, perispore with narrow wings, spiny ornamentation, few perforations. Scale bar 10 µm. Ting & Shih 796 (L) 3 Oleandra musifolia, perispore with wings partly replaced by fissures, irregularly warty ornamentation, few perforations. Scale bar 10 µm. Brooks s. n. (L 0317430) 4 Oleandra sibbaldii, perispore highly perforated. Scale bar 10 µm. Brass 29706 (L) 5 Oleandra wallichii, perispore spiny. Scale bar 10 µm. De Haas 2622 (L) 6 Oleandra wallichii, perispore spiny, spines confluent into ridges. Scale bar 10 µm. Van Steenis 20870 (L) 7 Oleandra sibbaldii. Perispore spines on a thin basal layer, exospore smooth, Scale bar 1 µm. Elmer 11451 (L) 8 Oleandra wallichii, perispore with thick basal layer, exospore smooth. Scale bar 1 µm. De Haas 2622 (L).