u 



ON ALYSICARPUS RUGOSUS D. C. AND ITS 

 ALLIED SPECIES. 



BY 



L. J. Sedgwick, F. L. S. 



It is a well-known crux whether the extremely diverse forms of 

 Alysicarpits which show a lomentum with the joints deeply and close- 

 ly transversely rugose belong to one species or several. De Candolle 

 (Prodr. I, 353) described two species, — A. styracifoUus and A. rttgosus. 

 Wight and Arnott (Prodr. I, 234) gave three, viz., A. styracifoUus 

 of De Candolle, and two new ones of their own, — A. Wallichii and 

 A Heyneanus. Baker (F. B. I. II, 159) reduced all previous descrip- 

 tions and all known specimens to one variable species, for which he 

 retained the name A. rugosus D.C., making A. styracifoUus D.C. and 

 A. Heyneanus Wt. & Arn. varieties, along with a third variety ludens 

 from the specific A. ludens of Wallich, and regarding Wight and 

 Arnott's A. Wallichii as a synonym of the type. Later floras (so far 

 as known to me) have followed Baker, several other varietal names, 

 however, having been added, viz., minor and pilifer both of Prain, and 

 probably others. 



While not denying that many of our Indian species need reduc- 

 tion, being merely local or edaphic forms, I am disposed to think that 

 the Indian Floras have often on the other hand given a wholly 

 exaggerated impression of morphological variability (as opposed to 

 plastic reaction to environment) through failure to detect the definite 

 characters dividing closely allied species ; and this would seem to be 

 the prevalent view at the present time. In particular I am convinced 

 that where in the same habitat two clearly distinguishable forms 

 exist side by side and do not merge they must necessarily be true 

 species. For this reason the field worker is an indispensable com- 

 plement to the herbarium systematist, inasmuch as he is able 

 to observe the innumerable plants around him, and note their de- 

 meanour. 



The fact that A. rugosus D.C, as understood since the F. B. I., 

 contains more than one species has been forced upon me by field 

 observations at various camps in the Dharwar District during the last 

 three seasons. For instance this winter on the black soil east of 

 Hubli, M. S. M. Ry., two quite distinct plants were abundant as weeds 

 in the fields. Their differences amounted to at least six characters. 



