Cyrtomium

Plants terrestrial or on rock. Stems erect or ascending, stolons absent. Leaves monomorphic, evergreen. Petiole ± 1/2–3/4 length of blade, base not swollen; vascular bundles more than 3, arranged in arc, ± round in cross section. Blade oblong-lanceolate, 1-pinnate with pinnae not lobed, distal pinnae only slightly smaller, blade ending in basally lobed pinna ± similar to lateral pinnae, papery or somewhat leathery. Pinnae not articulate to rachis, segment margins crenate to spinulose, sometimes also coarsely dentate; proximal pinnae not reduced, petiolulate, equilateral or somewhat inequilateral with acroscopic base more developed; costae adaxially grooved, grooves continuous from rachis to costae; indument of filiform scales abaxially, absent adaxially. Veins elaborately anastomosing, areoles formed with 1–3 included veinlets. Sori in 2 or more rows between midrib and margin, round. Indusia peltate, persistent or caducous. Spores brown, with inflated folds or wings. x = 41.

Distribution

North America, Asia, Africa including Madagascar, Pacific Islands (Hawaii).

Discussion

This difficult genus requires further systematic study. Estimates of species numbers have ranged from 9 (C. Christensen 1930) to 59 (Shing K. H. 1965). The group might better be considered a subgenus of Polystichum, from which it is poorly differentiated morphologically.

Species ca. 15 (2 in the flora).

Selected References

Ching, R. C. 1936. On the genus Cyrtomium Presl. Bull. Chin. Bot. Soc. 2: 85--106.

Christensen, C. 1930. The genus Cyrtomium. Amer. Fern J. 20: 41--52.

Shing, K. H. 1965. A taxonomical study of the genus Cyrtomium Presl. Acta Phytotax. Sin., Addit. 1: 1--48.

Lower Taxa

Cyrtomium falcatum, Cyrtomium fortunei

Key

1	Pinnae 4-10(-12) pairs, leathery, shiny adaxially, margins sometimes undulate or coarsely dentate, but not minutely crenulate or denticulate.	Cyrtomium falcatum
1	Pinnae (8-)10-25 pairs, papery, not shiny adaxially, margins minutely crenulate-denticulate.	Cyrtomium fortunei var. fortunei