Polypodiodes in Flora of China @ efloras.org

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.

1 Rhizome covered with whitish bloom and sparse scales or scales only present on very young part; segment margins entire (2)

+ Rhizome usually densely scaly, without whitish bloom; segment margins usually incised to serrate (5)

2 (1) Lamina abaxially glabrous (3)

+ Lamina abaxially pubescent (4)

3 (2) Rhizome scales usually absent; lamina adaxially pubescent only along rachis and costae. 1 P. formosana

+ Rhizome scales black, linear-subulate and with a broad brown base; lamina adaxially more uniformly pubescent. 2 P. raishaensis

4 (2) Rachis wings 2-3 mm wide; segments 0.5-1 cm wide. 3 P. niponica

+ Rachis wings ca. 5 mm wide; segments 1.2-1.4 cm wide. 4 P. wattii

5 (1) Rhizome scales light brown, 8-9 mm. 5 P. bourretii

+ Rhizome scales brown to dark brown or black, 2-5 mm (6)

6 (5) Rhizome scales linear-subulate, relatively sparse; segment margins entire. 3 P. niponica

+ Rhizome scales wider, usually concealing rhizome; segment margins incised to serrate (7)

7 (6) Lamina linear-lanceolate in outline; lateral segments up to 40-60 pairs (8)

+ Lamina ovate-lanceolate in outline; lateral segments usually 10-20 pairs (9)

8 (7) Scales black and subulate at upper part, brown at broad base, margin ciliate; fronds subglabrous. 6 P. lachnopus

+ Scales brown, lanceolate, margin irregularly denticulate; fronds pubescent on both sides. 7 P. pseudolachnopus

9 (7) Segment margins densely double-serrate (10)

+ Segment margins incised or incised-serrate (11)

10 (9) Rhizome scales ovate-lanceolate, brown, margin entire. 8 P. subamoena

+ Rhizome scales narrowly lanceolate, black, apex hairlike, margin denticulate. 9 P. hendersonii

11 (9) Rhizome 2-4 mm in diam., scales black; lamina segments 5-7 mm wide; sori close to costa. 10 P. chinensis

+ Rhizome 5-7 mm in diam., scales dark brown; lamina segments 15-20 mm wide; sori medial. 11 P. amoena

List of lower taxa