384 



COSMOS 



COSimOS (from the Greek word with a root idea of 

 orderliness; hence an ^ornament or beautiful thing, 

 which fits the present case ; finally and usually the uni- 

 verse, because of its orderliness). Oompisitce. A ge- 

 nus of at most 20 species of annual or perennial herbs, 

 all tropical American, mostly Mexican, often tall, usu- 

 ally glabrous: Ivs. opposite, pinnatelycut in the garden 

 kinds, in some others entire or lobed: fls. typically 

 shades of rose, crimson and purple, with one yellow 

 species, and white horticultural varieties, long pedun- 

 oled, solitary or in a loose, corymbose panicle : akenes gla- 

 brous : chaff of the receptacle in C. bipinnatus with a long 

 and slender apex, in other species with a blunt and short 

 apex. The genus is distinguished from Bidens chiefly 

 by the seeds, which are beaked in Cosmos but not dis- 

 tinctly so in Bidens, and by the color of the rays, which 

 in Cosmos is typically some form of crimson, while in 

 Bidens the rays are yellow or white. 



The "Black Cosmos" (C diversifoUus) is, perhaps, 

 better known to the trade as a Bidens or Dahlia. It has 

 the dwarf habit and dark red early fls. of some Dahlias, 

 but the akenes are very puzzling. They resemble those 

 of Bidens in being 4-angled, and not distinctly beaked. 

 They are unlike Bidens, and like Cosmos, in being not 

 distinctly compressed on the back. They resemble both 

 genera in having 2 rigid persistent awns, but, unlike 

 these genera, the awns have no retrorse barbs or prickles . 

 The akenes are linear, as in Cosmos and all our native 

 tropical species of Bidens; but, although narrowed at 

 the apex, they are not distinctly beaked, as in most spe- 

 cies of the genus Cosmos. The plant is, perhaps, near- 

 est to Bidens. 



Among the garden annuals that have come ™*<' promi- 

 nence in recent years, the Cosmos has a 

 most brilliant future. Until 1895 there 

 were in the two leading species only three 

 strongly marked colors: white, pink and 

 crimson. These and the less clearly de- 

 fined intermediate shades have all come 

 from C. bipinnatus ; the yellow forms have 

 come from O. sulphuretis , which was intro- 

 duced in 1896. Although Cosmos has been vastly im- 

 proved within the last five years, it still leaves much to 

 be desired and offers a most promising field to the plant- 

 breeder. The two species are still too lafp in coming into 

 bloom and too tall and weedy looking in their habit of 

 growth, but the season is being gradually shortened, with 

 dwarfer forms continually coming on, and it is neces- 

 sary to be patient while this interesting evolution is tak- 

 ing place. The chief improvement so far has been made 

 in California and in Georgia. In the east, for best results 

 it is still necessary to sow seed indoors in April and 

 transplant outdoors as soon as danger of frost is past. 

 Seed sown in the open ground often fails to produce 

 flowers in some northern localities before frost. The 

 slightest frost kills the typical species, but some of the 

 new strains are said to resist a degree or two of frost. 

 At first Cosmos fiowers were only an inch or two across. 

 The best varieties now average 3 inches, and some- 

 times reach i and 5 without thinning or disbudding. 

 Pure white fiowers of Cosmos are rarely if ever found 

 wild, but some of the cultivated varieties are nearly pure. 

 The group is totally lacking in bright reds. It would be 

 interesting to try for shades of red by crossing with 

 the dark blood-red G. diversifoUus (known as the 

 Black Cosmos, DaliUa Zimapani and Bidens atrosan- 

 guinea), which, however, would be a somewhat violent 

 cross, as that is a low-growing, early-flowering, tuberous- 

 rooted perennial. However, Cosmos is closely related to 

 Dahlia, Coreopsis, and Bidens, the first two being of 

 great garden importance and the latter, though weedy, 

 having possibilities. The rays of Cosmos bipinnatus are 

 typically oboordate in outline, narrow at the base, broad 

 at the apex and with three strongly marked teeth, which, 

 as in Coreopsis, are a great part of the characteristic 

 beauty of the flower. In the wild single Dahlia these 

 teeth are so short that they serve only to mar the sym- 

 metry of outline, and in the high-bred, cultivated varie- 

 ties of single Dahlias these teeth are practically if not 

 wholly obliterated. This will perhaps never happen to 

 the Cosmos, at least in America. On the contrary, the 

 rays of the Cosmos sometimes have an extra number of 

 teeth, often 6 or 7 altogether, and the effect is very 



COSMOS 



attractive and individual. Moreover, these teeth are often 

 somewhat wavy, giving the whole flower a frilled appear- 

 ance. The wild Cosmos is a stellate flower ; that is, it has 

 open spaces between its rays. These rays in cultivation 

 have broadened and rounded in outline and have over- 

 lapped, so that the new forms do not show any vacant 

 spaces between the rays but present a solid unbroken 

 face. This same tendency 

 has prevailed in the garden 

 evolution of many other fa- 

 vorites, notably the "shoul- 

 dered" Tulips, "rose-pet- 

 aled Geraniums," and single 

 Dahlias. The named varie- 

 ties of Cosmos may always 



564. Cosmos bipinnatus, 

 (X^.) 

 A otdtivated form. The rays of wild 

 flowers have only three teeth and 

 they are much more pronounced. 



