24. Aleuritopteris dubia (C. Hope) Ching, Hong Kong Naturalist. 10: 200. 1941.
中间粉背蕨 zhong jian fen bei jue
Cheilanthes dubia C. Hope, J. Bombay Nat. Hist. Soc. 12: 528. 1899; Aleuritopteris subrufa (Baker) Ching; C. leveillei Christ; C. subrufa Baker; C. wusukungii Miyamoto & H. Ohba.
Rhizomes erect, short; scales bicolorous, black with narrow brown margins, lanceolate. Fronds clustered. Stipe dark brown or black, lustrous, usually noticeably shorter than lamina, 5-15 cm × 1-2 mm, densely scaly and often with multicellular hairs; scales concolorous or somewhat bicolorous with lighter margins, narrowly lanceolate to hairlike. Lamina oblong to deltoid, 6-25 × 4-10 cm, pinnate-bipinnatifid, papery when dry, with white or pale yellow farina abaxially, also with hairlike to narrowly lanceolate scales along costae and midveins abaxially, glabrous or rarely sparsely hairy adaxially; pinnae 4-12 pairs, distinct along rachis, basal pair of pinnae ovate-deltoid, inequilateral, bipinnatifid; basal basiscopic segments larger than adjacent acroscopic ones; second and upper pairs of pinnae lanceolate, pinnatifid. Sori consisting of several sporangia, confluent at maturity. False indusia interrupted, with fimbriate margins.
Rock crevices on slopes, rock walls; 1300-2700 m. Guizhou, Sichuan, Yunnan [Bhutan, India, Kashmir, Nepal, Thailand].
Some specimens of Aleuritopteris dubia appear to be intermediate between A. dubia and A. albomarginata or A. rufa. The complex requires further study. Some of the intermediates may represent interspecific hybrids.