梧桐科一些属的分类位置探讨

COMMENTS ON THE TAXONOMIC POSITION OF SOME GENERA IN STERCULIACEAE

梧桐科（Ｓｔｅｒｃｕｌｉａｃｅａｅ）是锦葵目中的一个多型科，科的特征比较多样化．自从Ｅ．Ｐ．Ｖｅｎｔｅｎａｔ（１８３０）建立该科以来，对于该科范围和包含的属种数目，各国学者至今尚存在各种不同的看法．作者认为，火桐属（Ｅｒｙｔｈｒｏｐｓｉｓ）应当从梧桐属（Ｆｉｒｍｉａｎａ）中分出成为单独的属；午时花属（Ｐｅｎｔａｐｅｔｅｓ）不应归入锦葵科（Ｍａｌｖａｃｅａｅ），应当置于梧桐科；田麻属（Ｃｏｒｃｈｏｒｏｐｓｉｓ）与午时花属的形态特征很近似，可置于梧桐科的当比亚族（Ｄｏｍｂｅｙｅａｅ）中；梅蓝属（Ｍｅｌｈａｎｉａ）和平当树属（Ｐａｒａｄｏｍｂeｙａ）仍置于梧桐科．滇桐属（Ｃｒａｉｇｉａ）原归入椴树科（Ｔｉｌｉａｃｅａｅ），但因其花果形态与蚬本属（Ｅｘｃｅｎｔｒｏｄｅｎｄｒｏｎ）和柄翅果属（Ｂｕｒｒｅｔｉｏｄｅｎｄｒｏｎ）有很大差别，应单独成立为滇桐亚科（Ｃｒａｉｇｉｏｉｄｅａｅ Ｓ．Ｊ． Ｘｕ ｅｔ Ｈｓｕｅｓｕｂｆａｍ． ｎｏｖ．）。

Sterculiaceae is a polytypic family with greatly diverse characteristics in Malvales. Till now many authors have no uniform agreement on the demarcation and the numbers of genera since E. P. Ventenat established this family in 1830. According to our studies, we agree that Erythopsis should be separated from Firmiana. Pentapetes should not be placed in Malvaceae, its characters are quite different from that of Malvaceae, so it is better to maintain it in the Sterculiaceae. On account of the pollen morphology and some other characters, Craigia is similar to that of some genera of Tiliaceae, and should be placed in Tiliaceae, but the flower and fruit characters of which are quite different from Excentrodendron and Burretiodendron, so we suggest establishing a new subfamily, namely Craigioideae S. J. Xu et Hsue subfam. nov. in the Tiliaceae to accommodate the Craigiae. Pentapetes, Corchoropsis, Paradombeya and Melhania should be placed in Sterculiaceae.