Cyclosorus (Pneumatopteris) florencei A. R. Sm. & Lorence, 2011

Lorence, David H., Wagner, Warren L., Wood, Kenneth R. & Smith, Alan R., 2011, New pteridophyte species and combinations from the Marquesas Islands, French Polynesia, PhytoKeys 4, pp. 5-51 : 24-25

10. Cyclosorus (Pneumatopteris) florencei A. R. Sm. & Lorence sp. nov. Fig. 12

Latin.

A C. glandulifero (Brack.) Copel. absentibus falcatis, acicularibus pilis adaxialliter supra axiales costas et presentibus reductarum proximalium pinnarum paribus non tan numerosis (ca. 10 pro ca. 20), absentibus pilis supra sporangiales stipites et et receptacula differt.

Type.

Marquesas Islands: Hiva Oa: Atuona, trail to Hanamenu, 9°48'S, 139°04'W, wet forest, 29 Jul 1988,J. Florence (with D. Lorence, S. Perlman) 9598 (holotype BISH!; isotypes P, PAP, neither seen).

Description.

Terrestrial ferns; rhizomes creeping, to 10 mm in diameter; fronds spaced, base of stipes sparsely scaly, scales brown, lanceolate; stipes to ca. 70 cm long below first large pinnae, distal part of stipes to 9 mm in diameter at base, bearing ca. 10 pairs of greatly reduced pinnae 2.5-4 cm apart, these 1-10 mm long; proximal large pinnae narrowed at their bases; blades subcoriaceous, excluding reduced, glanduliform proximal pinnae, to ca. 60 cm long, gradually reduced distally to a pinnatifid apex; rachises tan to stramineous, glabrous; large developed pinnae to ca. 30 lateral pairs, to ca. 12 × 1.7 cm, at their bases each with a swollen, conical aerophore to ca. 0.5 mm long, pinnae bases not auricled, apices caudate-acuminate, lobed 2/5-1/2 toward the costae (3-4 mm from costae), lobes oblique and slightly falcate, subacute to rounded at tip; costules ca. 4 mm apart; veins to ca. 8-9 pairs per segment, prominent (especially abaxially) on both sides of laminae, the basal pair from adjacent segments generally obtusely united and producing an excurrent vein 2.5-3 mm long to the sinus, the next 1-1 1/2 pairs merging with this excurrent vein or running to a cartilaginous, raised, sinus membrane; abaxial surface of rachis, costae, costules, and veins nearly lacking hairs or with scattered, minute hairs less than 0.1 mm, costae bearing adpressed to slightly spreading, tan, amorphous (cell walls not readily discernible at 30 ×) scales to 2 × 0.2 mm; yellowish sessile glands absent on both laminar surfaces, pustules also lacking; hairs absent adaxially on costae, costules, and veins. Sori medial to supramedial; indusia absent; sporangia bearing yellowish capsular glands ca. 0.1 mm, lacking acicular hairs on sporangia and from receptacles.

Distribution.

Hiva Oa, Marquesas Islands, known only from the type collection made along the trail from Atuona to Hanamenu.

Ecology.

Occurs in montane wet forest with Crossostylis biflora , Freycinetia sp., Metrosideros collina , Weinmannia marquesana var. marquesana and other species characteristic of this habitat.

Etymology.

We take pleasure in naming this new species for Jacques Florence (1951-) who has done so much to advance our knowledge of the flora of the Marquesas Islands and that of French Polynesia in general.

Conservation status.

Proposed IUCN Red List Category Critically Endangered (CR); B2a, B2b i–iii; D): B1, extent of occurrence estimated to be less than 100 km2; B2, area of occupancy estimated to be less than 10 km2 (ca. 9 km2), and B2a, a single population known; b ( i–iii), habitat continuing decline inferred; D, population estimated to number fewer than 250 mature individuals. The suitable habitat for Cyclosorus florencei on Hiva Oa (ca. 315 km2) is indicated as an endangered environment, threatened by human activity (deforestation and fire), feral animals, and invasive plants, reducing the extent of the forest; and D, the rarity of this species is supported by the lack of collections and the small extant area within a commonly collected island, i.e. with a single collection.

Discussion.

This new species is perhaps most closely related to Cyclosorus glanduliferus (Brack.) Copel., from Rarotonga (Cook Islands), Samoa, Solomon Islands, and New Hebrides, and to Cyclosorus stokesii (E. D. Br.) Ching, known only from Rapa Iti in the Austral Islands ( Holttum 1977). The three species are similar in rhizome habit, blad e dissection, and blade size. However, Cyclosorus glanduliferus differs from Cyclosorus stokesii in having more numerous glanduliform pinnae along the stipes (to about 20 pairs), longer aerophores at bases of costae, presence of small aerophores at costule bases, fewer and shorter costal scales, presence of numerous acicular, falcate hairs on the costae adaxially, and hairs borne on the sporangial stalks and receptacles. From Cyclosorus stokesii , Cyclosorus florencei differs in having less scaly stipe bases (scales numerous and ovate in Cyclosorus stokesii ), fewer pairs of glanduliform proximal pinnae (to 20 pairs of glanduliform pinnae in Cyclosorus stokesii ), lacking aerophores at bases of costules, more numerous, longer costal scales, 4-5 pairs of veins uniting below sinus or connivent at the sinuses, and lacking hairs from the sporangial stalks. Spore differences mentioned by Holttum (1977) between Cyclosorus glanduliferus and Cyclosorus stokesii cannot be evaluated for Cyclosorus florencei because the sporangia in the type of Cyclosorus florencei are immature. The label with the type indicates the presence of small pustules abaxially, but we fail to see any pustules of the kind often found in species of subg. Pneumatopteris ; we do see numerous, slightly more reflective stomates (guard cells) at 30 times magnification. Until now no species of subg. Pneumatopteris has been recorded from the Marquesas Islands.

The following new combination in Thelypteridaceae is also required.

Figures

Figure 12. Cyclosorus florencei A. R. Sm. & Lorence Holotype collection with frond and part of rhizome, Florence et al. 9598 (BISH). Inset shows detail lower surface of fertile pinna with sori.