Orthiopteris trichophylla Copel.

Luong, Thien Tam, Hovenkamp, Peter H. & Sosef, Marc S. M., 2015, Revision of the fern genus Orthiopteris (Saccolomataceae) in Malesia and adjacent regions, PhytoKeys 53, pp. 39-71 : 59-60

8. Orthiopteris trichophylla Copel. Figs 2d , 3d

Orthiopteris trichophylla Copel., Univ. Calif. Publ. Bot. 18: 217. 1942.

Saccoloma trichophyllum (Copel.) G.B.Nair, J. Econ. Taxon. Bot. 16(3): 643. “1992” [1994]. Type. Based on Orthiopteris trichophylla Copel.

Type.

PAPUA NEW GUINEA. Idenburg River, 15 km southwest of Bernhard camp, alt.1800 m, 1939, Brass 12027, (erroneously cited as Brass 12057 in Copeland 1942, holo: MICH, 1190791* [http://quod.lib.umich.edu/h/herb2ic/x-mich1190791/mich1190791.tif]; iso: BM, 001044444, BO 1510941)

Description.

Rhizome erect. Rhizome scales not seen. Fronds 120-160 × 40-50 cm; stipes stout, 40-50 cm long, 0.4-0.6 cm across (at base), dark brown; lamina deltoid, widest at base, tripinnate to quadripinnate, 100-120 × 40-50 cm, herbaceous, dark brownish green when dry, glabrous or with few scattered scales; pinnae at 30-35° to rachis, largest at base, overlapping, stalk 0.5 cm, including stalk 15-25 × 6-9 cm, lanceolate, first basiscopic pinnules of lowest pinnae enlarged; ultimate segments 1.0-1.5 × 0.5 cm, sessile or very short stalked, trapezoid, apex acute, margin with weak cartilaginous border; almost completely dissected to less than 0.2 mm from veins; lobes narrowly oblong, veins in lobes unbranched or with 1 fork, dark brown and not contrasting with lamina, percurrent. Scales on rachis mostly at base of pinnae or pinnule, very few on veins, hair-like. Sori lateral or apical on lobes, symmetric, slightly reflexed, slightly concave with lamina wings slightly recurved, 1.0-1.2 × 0.6-0.7 mm, funnelform, widest at mouth, not wider than the sterile lamina below sorus; inner indusium dull brown, firm, 4/5-2/3 as long as outer indusium, apex truncate; outer indusium truncate; sporangia 7-12 per sorus, capsule globose and rounded at apex, gradually narrowed toward base, indurated annulus cells 16-20, ± equal; spores in polar view not studied, in lateral view.

Distribution.

Papua New Guinea (Idenburg River).

Ecology.

Terrestrial in bottom of ravines, rain forest, at 1800 m altitude.

Discussion.

This species can be mistaken for Orthiopteris cicutarioides because the frond morphology is similar, with fronds very finely dissected in both species. However, Orthiopteris trichophylla is more finely dissected with a single vein per lobe (similar to Orthiopteris ferulacea ), while Orthiopteris cicutarioides has 2 or 3 one veins per lobe. The sori and indusia of Orthiopteris trichophylla resemble those of Orthiopteris campylura var. kingii , being funnelform and slightly reflexed, and the possibility cannot be excluded that Orthiopteris trichophylla is locally derived from Orthiopteris campylura var. kingii . The single specimen we examined (Brass 12239) differs slightly from the type (studied from scanned image of Brass 12027) by its shorter lobes. However, the sori and indusia are identical, and they were collected on the same day and at the same locality. Unlike in Orthiopteris trichophylla , which may represent a similar case of a locally derived taxon, both specimens of Orthiopteris cicutarioides look very productive with many ripe sporangia spreading over the mouth of the sorus. Brass noted that the species was very common and abundant at the collecting site (Idenburg river), but we have not seen any later collections than Brass’s in 1939. Perhaps it is just abundant locally, and it may well be currently threatened.

Figures

Figure 2. Ultimate segments. Arrows show distance from base of the shallowest sinuses to nearest costule / vein. a Orthiopteris ferulacea, Smith 8932 (K) b Orthiopteris cicutarioides, Carr 13257 (K) c Orthiopteris samoensis, Reinecke 97 a (L) d Orthiopteris trichophylla, Brass 12239 (L) e Orthiopteris campylura var. cautada, Carr 12518 (L) f Orthiopteris campylura var. laxa Mueller s. n. (L) g Orthiopteris campylura var. kingii, Brass 12941 (MICH) h Orthiopteris henriettae, Lam & Meeuse 5892 (L) i Orthiopteris campylura var. insularis Braithwaite 4110 (L). All scale bars 1 mm.

Figure 3. Sori of Orthiopteris seen from abaxial side. a, b Orthiopteris campylura var. campylura (Cuming 119, MICH) c Orthiopteris campylura var. kingii (Brass 12941, MICH) d Orthiopteris trichophylla (Brass 12239, L) e Orthiopteris tenuis (Smith 9154, L) f Orthiopteris tenuis (Smith 7274, L) g Orthiopteris campylura var. caudata (Carr 12518, L) h Orthiopteris cicutarioides (Carr 13257, K) i, j Orthiopteris campylura var. insularis (Braithwaite 4110, L) k Orthiopteris tenuis (small segment) (Degener 14648, L) l Orthiopteris ferulacea (Smith 8932, K) m, n Orthiopteris firma (Schlechter 14890, L) o, p Orthiopteris campylura var. laxa (Mueller s. n., L) q, r Orthiopteris henriettae (Lam & Meeuse 5892, L) s Orthiopteris henriettae. t Orthiopteris samoensis (Reinecke 97 a, L) u, v Orthiopteris samoensis (Vaupel 312, L). All scale bars 1 mm, oi = outer indusium, ii = inner indusium.