1926] Babcocl-Lcsley : Chromosomes and Taxonomic Belationships 317 



botanic gardens in numerous institutions. Many taxonomic and other 

 treatises on the Compositae have been consulted, which cannot be cited 

 in this brief paper. 



TAXONOMY AND CYTOLOGY OF T\VEXTY-OXE 8PECIES 



OF CREPIS 



In the present paper we do not wish to discuss the taxonomy of 

 Crepi'sAn detail or to propose any taxonomic revision of the genus, but 

 merely to set forth the general features of the group and its sub- 

 divisions in such a way as to enable the reader to appreciate some of 

 the difficulties involved in attempting to classify the species according 

 to a natural system. Also, it is hoped that the significance of the cyto- 

 logical data herein presented will be clearer after a preliminary con- 

 sideration of the outstanding morphological resemblances and differ- 

 ences to be found within this group of plants. 



No thoroughgoing investigation of the entire genus has been made. 

 Some of the species have been studied since the time of Linnaeus or 

 even earlier, and at least forty-four other generic names have been 

 applied by twenty-four authors in attempting to classify various por- 

 tions of the assemblage. The purposes of the present paper can be 

 best served by a discussion of the treatment of the genus given by 

 Hoffmann in Engler and Prantl's Pflanzenfamilien. This treatment, 

 represented in condensed form below, includes all but six of the twenty- 

 one species for which complete data as to chromosome size are avail- 

 able and one other (C. patula) which Ave have not yet been able to 

 secure. The six species referred to — hlattariaides Vill., bursifolia L.. 

 neglecta L., parviflora Desf., montana d'Urville, and setasa Hall. f. — 

 are all easily placed in Hoffmann's categories with the exception of 

 iteglecta, which is referred to Eucrepis in most recent floras (see p. 

 327). A translation of Hoffmann's description of the genus is given 

 below for the information of readers who are not familiar with this 

 groups of plants. His analysis of the genus and key to the sections 

 appear in table 1. 



Crepis L. — Heads small to rather large, yellow- or seldom red- 

 flowered, borne singly or in panicles of variable form ; involucre cylin- 

 drical or bell-shaped, often with loose or appressed outer calyx, the 

 inner fructiferous bracts often becoming stouter and harder through- 

 out or along the middle nerve ; receptacle naked or ciliate ; fruit 10-30 

 ribbed, with a short callosity on the base, reduced or beaked at the 

 apex, the outer fruits sometimes shaped differently from the inner 

 ones ; pappus in most species composed of soft pliable hairs, seldom 

 somcAvhat brittle and brownish, in the marginal fruits sometimes lack- 

 ing. — Herbs, veiy seldom half-shrubby plants. Perhaps 170 species 

 mostly from the northern hemisphere. 



