14. Polypodiodes Ching, Acta Phytotax. Sin. 16(4): 26. 1978.
水龙骨属 shui long gu shu
Authors: Shugang Lu & Peter H. Hovenkamp
Plants medium-sized. Rhizome long creeping, mostly densely scaly, with whitish bloom when scales sparse; scales brown to dark brown, lanceolate to ovate-lanceolate, clathrate, peltate at broad base, margin entire, denticulate, or ciliate, apex acuminate or hair-shaped. Fronds remote, articulate to rhizome; stipe straw-colored or brown, scaly at base; lamina deeply pinnatisect, oblong-lanceolate in outline; segments 10-60 pairs, narrowly lanceolate, bases confluent through narrowly winged rachis, rarely lowermost free, margin toothed or serrulate, apex acuminate. Veins usually anastomosing to form a row of very narrow areoles on each side of costa and 1 or 2 rows of much broader areoles along each side of costules, latter each including a free veinlet. Lamina herbaceous, glabrous or pubescent, usually minutely scaly abaxially. Sori orbicular, in single rows on each side of costules, each at end of included veinlet, superficial or sunken, paraphyses soon lost; sporangia long stalked, annulus with 12-19 hardened cells; spores ellipsoid, surface coarsely verrucate. x = 37.
About 17 species: mostly confined to tropical and subtropical Asia; 11 species (three endemic) in China.
Christenhusz et al. (Phytotaxa 19: 38. 2010) and Lindsay and Middleton (http://rbg-web2.rbge.org.uk/thaiferns/factsheets/index.php#P; accessed 2 Apr 2012) include Polypodiodes within Goniophlebium.
The following taxa are excluded from the present treatment, pending further research: Polypodiodes falcipinnula S. K. Wu & J. Murata (Acta Phytotax. Sin. 39: 70. 2001), described from Yunnan, and P. paramoena Ching & Y. X. Lin (Acta Phytotax. Sin. 22: 400. 1984), described from Xizang.