Diplaziopsidaceae X.C.Zhang & Christenh.

Christenhusz, Maarten J. M., Zhang, Xian-Chun & Schneider, Harald, 2011, A linear sequence of extant families and genera of lycophytes and ferns, Phytotaxa 19, pp. 7-54 : 15

Family 34. Diplaziopsidaceae X.C.Zhang & Christenh. , fam. nov.

3 genera ( Diplaziopsis ( type of the family), Hemidictyum , Homalosorus ).

Filices mediocres vel grandes; rhizomatibus crassis, erectis vel decumbentibus; laminis 1-pinnatis, imparipinnatis, pinnis integris, glabris; venis lateralibus utroque costulae latere discretis sed margines versus reticulatim anastomosantibus, areolarum 2–4 series facientibus, sine venulis discretis inclusis; soris secus venas longas prope costulam elongatis, indusio similiter elongato membranaceo obtectis; indusiis plerumque 3–8 mm, interdum ad 1–2 cm longis, arcuatis, allantoideis; numero basico chromosomatum x=31, 40, 41. Genus quod est typus familiae: Diplaziopsis C.Chr.

Description: Medium or large ferns, usually in forests near or by streams. Rhizomes decumbent to erect, thick; lamina 1-pinnate, imparipinnate, with pinnae entire, glabrous; veins free on either side of the midrib, but fully anastomosing toward the margins where they form 2 – 4 rows of areoles, without included free veinlets; sori elongate along the long veins close to the midrib, covered by a similarly elongates, membranous indusium; indusia usually 3 – 8 mm, sometimes up to 1 – 2 cm long, arched, sausage-like; spores with wing-like fimbriate and echinate folds, or low perforate plain folds. X=41, 40 or 31.

Notes:— Homalosorus pycnocarpos (Spreng.) Pic.Serm. has been transferred to Diplaziopsis by Price (1990). Different from the Asian Diplaziopsis with x=41, the temperate North American Homalosorus pycnocarpos has x=40 and the tropical American genus Hemidictyum marginatum with x=31. Hemidictyum was first shown to be sister to the Aspleniaceae by Schuetpelz & Pryer (2007), but no Diplaziopsis was included in their study. Here, we incorporate new evidence generated in the laboratory of X.-C. Zhang , and place these genera in one family ( Wei et al. 2010). The inclusion of Hemidictyum in Diplaziopsidaceae is however still tentative; further studies will have to confirm its placement.