蜡梅科植物的分支分析

CLADISTIC ANALYSIS OF CALYCANTHACEAE

蜡梅科是一个仅有４属，１０种的小科，将蜡梅科的生物信息数字化，利用徐克学的和谐性分析程序，剔除了不合理的性状安排，判别关系含糊的性状极性，利用最大同步法，最小平行演化法及最大离散量分支分类法，对由性状再分析后获得的数值矩阵进行运算，推导分支图，明确各属之间的发生、发展和演化的关系。结果表明：椅子树亚科（Ｉｄｉｏｓｐｅｒｍｏｉｄｅａｅ）的椅子树属（Ｉｄｉｏｓｐｅｒｍｕｍ Ｂｌａｋｅ）在整个蜡梅科（Ｃａｌｙｃａｎｔｈａｃｅａｅ）的演化水平中是最高的，它的进化性状最多，同时它与蜡梅亚科（Ｃａｌｙｃａｎｔｈｏｉｄｅａｅ）的其它三个属很早就按照各自的方向平行演化了，蜡梅亚科的蜡梅属（ＣｈｉｍｏｎａｎｔｈｕｓＬｉｎｄｌｅｙ）表现的属性最原始，它是从蜡梅科的祖先中分离出的最早类群，随后夏蜡梅属（Ｓｉｎｏｃａｌｙｃａｎｔｈｕｓ Ｃｈｅｎｇ ＆ Ｓ．Ｙ．Ｃｈａｎｇ）与美国蜡梅属（Ｃａｌｙｃａｎｔｈｕｓ Ｌ．）从蜡梅科祖先中相继分离出来，这两个属的亲缘关系最近，拥有许多共同的性状．

Calycanthaceae is a small family with 4 genera and 10 species. In the present paper, a cladistic analysis is made using the methods of Maximal Same Steps, Minimal Parallel Evolution and Synthetic Maximal Diversity Method developed by Xu. According to the cladistic analysis, it is suggested that Chimonanthus may be an earliest branch from pre-Calycanthaceae, which almost retains all primitive characters of the ancestor, while Sinocalycanthus is closely related to Calycanthus. Both Sinocalycanthus and Calycanthus are of transit genera from primitive to advanced taxa in the Calycanthaceae, and Idiospermum is the most advanced in the family.