Dryopteris rheophila Mitsuta ex Darnaedi M.Kato & K.Iwats.

Family

Dryopteridaceae

Nomenclature

Dryopteris rheophila Mitsuta ex Darnaedi, M.Kato & K.Iwats., J. Jap. Bot. 64: 302. 1989; Tagawa & K.Iwats., Fl. Thailand 3: 620. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 205. 2000.

Description

Rhizome erect; rhizome scales persistent, dull brown, ovate, lip to 7 by 4 mm. Stipes 10–40 cm long; laminae oblong-lanceolate to narrowly deltoid-ovate, bipinnate to obscurely tripinnatifid, 17–43 by 7–18 cm; pinnae inserted at angles less than 50° to rachis, middle pinnae oblong, broadest at base, acuminate towards apex, 5–11 by 2–3 cm; pinnules oblong, unequally cuneate at base, obtuse at apex, shallowly lobed, each lobe with a short sharp tooth. Sori medial on acroscopic veinlets, distributed throughout lamina; chromosome number n = 82, 2n 164 (tetraploid</A>); reproduction sexual.

Distribution in Thailand

NORTH-EASTERN: Loei.

Wider Distribution

Endemic to Thailand.

Ecology

On sandstone boulders in streamlet at 1000–1200 m alt.

Similar species

Dryopteris sparsa (D.Don) Kuntze

Proposed IUCN Conservation Assessment

Data Deficient (DD). This species is only known from Phu Kradueng in Loei Province.  The overall distribution of the species there, and the health of the population, requires further research to provide a conservation assessment.

Notes

Part of a species complex including Dryopteris sparsa (D.Don) Kuntze, the taxonomy of which requires clarification.

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