safford: notes on dahlia 367 



heading "De Acocoxochitl seu flore Acocotli," as having flower 

 heads with yellow disk and purple ray-florets, after which the 

 author goes on to say that many more forms of Acocoxochitl 

 occiu" in Mexico, differing from one another in the size and color 

 of the flowers, some of them white, others yellow, others purple 

 or red, others white tinged with purple, or perhaps yellow tinged 

 with red, and a great many other kinds, in some cases with double 

 or multiple whorls of ray flowers, either forming circles or clus- 

 tered in compact bunches {manipuli) . The roots he describes as 

 fleshy, or succulent, and fascicled like those of asphodel, with a 

 resinous or somewhat sweetish artichoke-Hke taste. 



Although both the flowers and leaves of cultivated dahlias 

 show considerable variation, yet there are certain features in 

 both which are more or less uniform. In one group of the genus 

 the ray-florets are broad and flat; in another they have a ten- 

 dency to become involute or quilled, while in a third the margins 

 are bent backward or revolute. These distinct groups are further 

 characterized by their foliage, the leaves of which, whether sim- 

 ple, pinnate, or bipinnate, have a peculiar texture and vary simi- 

 larly in form. Very little attention is paid to the leaf -charac- 

 ters of dahhas either in standard works on horticulture or in 

 florists catalogues. A well defined species like Dahlia coccinea, 

 for instance, may be found under the heading leaves once pinnate, 

 in spite of the fact that in the original drawing of the type plant 

 the lower leaves of this species have their lower pinnae again 

 pinnate. In consequence of this carelessness and also perhaps 

 from the fact that the lower leaves of the forms figured in cata- 

 logues are seldom shown, some authors have gone to the extent 

 of uniting into a single species Cavanilles' Dahlia pinnata, D. 

 rosea, and D. coccinea. 



In nearly all the monographs on the genus Dahlia hitherto 

 published the different varieties have been grouped from the 

 horticulturalists' point of view, according to the forms of the 

 flowers, under such headings as "single, duplex, anemone-flow- 

 ered, collarette, pompon, fancy, decorative, peony-flowered, and 

 cactus dahlias," without identifying the single-flowered forms 

 with botanical species (except perhaps in Dahlia coccinea and 



