Biosystematic Investigations with Acorus – 4. Communication¹. A Synthetic Approach to the Classification of the Genus

Abstract

The genus Acorus (Araceae–Acoroideae) comprises two polytypic species, the diploid A. gramineus Soland. and A. calamus L. The latter forms with three cytodemes a supposedly autopolyploid series (2x, 3x, 4x). A study of morphological, anatomical (fig. 1–6) and histochemical characters of the 49 Acorus samples used previously for caryological and chemical (essential'oils) investigations resulted in a proposal for an unambiguous classification of Acorus. Identification (see key) of non–flowering samples is possible without counting chromosomes. The proposed classification accepts two species and three varieties:

1. A. gramineus Soland.; diploid, mostly fertile; morphologically, ecologically and chemically variable.

2. A. calamus L.; aggregate species:

   • a) var. americanus (Raf.) Wulff; diploid and fertile; morphologically fairly homogenous; two chemotypes with respect to essential oils.

   • b) var. calamus (= var. vulgaris L.); triploid and totally sterile; morphologically and chemically homogenous.

   • c) var. angustatus Bess.; tetraploid and variable in many respects ; partly fertile; two chief ecotypes, a (subtropical one and a temperate one; several chemotypes. If for practical purposes a formal name is considered desirable for the (sub)tropical ecotype, the name var. verus L. is available.

Key Word Index

Classification of Acorus - Araceae - Acoroideae - Acorus calamus - Acorus gramineus - Polyploidy - Procyanidins - Myriophyllin Cells - Idioblasts - Aerenchyma - Sclerenchyma - Indian Oil of Calamus - Asarone