CONTRIBUTIONS FROM THE GRAY HERBARIUM OF HARVARD 

 UNIVERSITY, NEW SERIES, NO! XX. 



By B. L. Robinson. 



Presented March 13, 1901. Iteceived March 16, 1901. 



J. _ SYNOPSIS OF THE GENUS MELAMPODIUM. 



In the following key to Melampodium the genus is limited as by Ben- 

 tluira and Hooker in their Genera Plantarum and by Hoffmann in Eugler 

 & Prantl's Natiirlichen Pflanzenfamilien. It will, therefore, be unneces- 

 sary here to reproduce the generic description or give generic synonymy. 

 The key is based chiefly upon the material which has accumulated in the 

 Gray Herbarium, including the recently acquired Klatt collection and 

 some borrowed material from the U. S. National Museum. The writer 

 has also in connection with this work been kindly permitted by Mr. 

 Casimir de Candolle to examine and trace the types in the Prodromus 

 Herbarium. Much difficulty has been experienced in giving the species 

 a natural sequence, and after many efforts the hope of securing such an 

 arrangement has been abandoned. The employment of pubescence in 

 grouping the species of this genus is new and appears to yield more satis- 

 factory results than an implicit reliance upon the fructiferous bracts. 

 The latter, as is well known, often surpass the achenes, forming above 

 them a cup or hood. This hood is often pointed dorsally at the summit 

 and the point may be recurved or spirally coiled. Unfortunately, how- 

 ever, these features, the hood and its appendage, show too great varia- 

 bility in certain nearly related forms, such as M. sericevm and its 

 varieties, to yield diagnostic characters of the first rank. However, the 

 presence or absence of a hood can usually be determined readily, and 

 the two sections Emnelampodium and Zarabellia may conveniently be 

 retained. 



Bentham and Hooker, 1. c, estimated the species at eighteen, and 

 Hoffmann, 1. c, accords twenty-five species to the genus. It will be 

 seen, however, that this number can. with our present knowledge, be 

 somewhat increased. The genus reaches its greatest development in 

 Mexico, where, if we include Lower California and Central America, no 

 less than thirty-one species occur. Of these species three reach the 

 southern United States (one merely as an introduction), two are found 



