Volume 3 > Part 1 > Year 1979 > Page 45–46 > Osmundaceae > Osmunda

2. Osmunda angustifolia Chingwfo-0001118110

Acta Phytotax. Sin. 8: 131, 160.f. 10. 1959; Fl. Reipubl. Popularis Sin. 2: 84. 1959; Tagawa & K.Iwats. S.E. Asian Stud. 5: 34. 1976. Fig. 3: 1-3.

Accepted Name : This is currently accepted.

Description : Fronds congested at apex of rhizome. Stipes stramineous, short, up to 25 cm long; laminae pinnate with a distinct apical pinna, moderately acute at apex, a few pairs of basal pinnae slightly shortened; lateral pinnae linear, gradually narrowing both towards acute apex and towards shortly stalked base, less than 15 cm long, 1.2 cm broad, the margin slightly waved, the sinus usually less than 1 mm in depth; the veins two or three times dichotomously branching; texture papyraceous to softly coriaceous, fresh green in colour; a few middle pinnae fertile, contracted, brown after shedding the spores.

Thailand : NORTH-EASTERN: Phetchabun (Phu Miang), Loei (Phu Luang, Phu Kradueng); SOUTH-EASTERN: Trat (Ko Chang).

Distribution : Hainan (type), Hongkong, China (Kwangtung), Taiwan (?).

Ecology : On sandy banks or on wet rocks usually along streams in dense forests or in half shaded areas at medium altitudes.

Vernacular : Hatsadam (หัสดำ)(Northeastern).

Notes: This is distinguished from Osmunda banksiifolia (Pr.) Kuhn, Ann. Lugd. Bat. 4: 299. 1869 of E Asia by the smaller size of the plants. The sterile pinnae are less than 12 cm long, 8 mm broad, though more than 15 cm and 12 mm in O. banksiifolia. The breadth of the pinnae is the only reliable indicator to separate O. angustifolia from O. banksiifolia. The sterile pinnae are numerous and closely placed together in O. angustifolia but there are no other distinct features to distinguish O. angustifolia from O. banksiifolia.

E-version notes : For more details see Ferns of Thailand, Laos and Cambodia.