21. Caobangia A. R. Smith & X. C. Zhang, Novon. 12: 546. 2002.
高平蕨属 gao ping jue shu
Authors: Zhang Xianchun & Alan R. Smith
Rhizomes long creeping, filiform, sparingly branched, approximately terete, dorsiventral with 2 rows of dorsal fronds, rather sparsely set with roots, not ant-inhabited, densely scaly; scales dark red-brown, lacking hairs at bases (non-comose), acicular and subentire from peltately attached, clathrate, dentate bases. Fronds shortly stipitate to subsessile; stipe lacking obvious articulation lines or swellings at bases, with scales similar to those of lamina; lamina herbaceous to papery, monomorphic to slightly dimorphic in size and shape (sterile seemingly often shorter and more rounded at base, but equaling fertile in width), narrowly elliptic (fertile) to ovate (sterile), dark green-brown when dried, stellate hairs lacking, densely scaly on both sides with persistent red-brown, hairlike scales; scales with peltate, clathrate, laciniate-margined bases and very long, uniformly red-brown, non-clathrate dentate to laciniate tips. Venation: midribs distinct, sclerenchymatous (darkened, but hidden by red-brown scales), main lateral veins indistinct or distinct only in basal 1/5 or less in cleared fronds, 10-13 per side, anastomosing and forming irregular areoles (1 row of large areoles adjacent to midrib, 0-2 additional rows of smaller areoles toward margins, areoles with occasional free veinlets, these simple (not forked), almost always recurrent, sunken, not or only faintly visible adaxially, hydathodes lacking. Sori in single rows within larger areoles, midway between midrib and each margin, orbicular, not confluent, ± obscured by acicular scales especially when sporangia are immature. Sporangia stalked, lacking paraphyses, with 16-19 hardened annulus cells, mixed with acicular scales; spores monolete, whitish, papillate to rugose.
One species: China, Vietnam.
Caobangia is a monotypic genus, easily identified by its very distinctive hairlike scales. Molecular evidence shows that it is most closely related to Lemmaphyllum where it was included by Li Wang et al. (Bot. J. Linn. Soc. 162: 36. 2010).
