A linear sequence of extant families and genera of lycophytes and ferns Author Christenhusz, Maarten J. M. Botany Unit, Finnish Museum of Natural History, Postbox 7, University of Helsinki, 00014 Helsinki, Finland. & Department of Botany, Natural History Museum, Cromwell Road, London SW 7 5 BD, United Kingdom. Author Zhang, Xian-Chun State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China. E-mail: zhangxc @ ibcas. ac. cn Author Schneider, Harald Department of Botany, Natural History Museum, Cromwell Road, London SW 7 5 BD, United Kingdom. text Phytotaxa 2011 2011-02-18 19 7 54 http://biotaxa.org/Phytotaxa/article/view/phytotaxa.19.1.2 journal article 6238 10.11646/phytotaxa.19.1.2 57ebbaea-ebc2-443f-8066-60a0c5ea774f 1179-3163 4893995 16F684F2-12C4-4A33-9330-062AC1F32FF0 Family 37. Rhachidosoraceae X.C.Zhang , fam. nov. Based on a full and direct reference to the Latin description associated with Athyriaceae subfam. Rhachidosoroideae M.L.Wang & Y.T.Hsieh, Acta Phytotax. Sin . 42: 527 (2004) . 1 genus. ( Rhachidosorus Ching , type of the family). Description:—Medium to large ferns in forest often at rocky (limestone) places. Rhizomes thick, erect to decumbent, apeices and bases of stipes densely covered in scales; laminae 2 – 3-pinnate, deltoid to ovatedeltoid; sori linear, falcate, touching midveins at proximal ends, subparallel to midveins; indusia more or less thick, entire, on acroscopic side of lateral veinlets, asplenioid, spores with tuberculate folds. X=40. A genus with ca. 7 species, distributed in east and southeast Asia, from Japan to Sumatra and the Philippines . Rhachidosorus was not included in Schuettpelz & Pryer (2007) and the results of Wang et al. (2003 , 2004) were not accepted by Smith et al. (2006a , 2008 ).