| 
| 
} 
REGIONS AND AREAS OF DISTRIBUTION. 
499 
Genera. American races. Common races. | Old-World races. 
| 
HYPOCH(ERIS...| About 25 species, South | Sections Achyrophorus | About 10 species, Medi- 
American, chiefly An- | and Serioloides, but no | terranean and Euro- 
dine or extratropical. common species except | peeo-Asiatic, including 
H. glabra, L., and H. | the common sections 
radicata, L., probably | and small endemic sec- 
colonists in most sta- | tions. 
tions. 
Connexions ...| Leontodon the nearest. |... eene Leontodon the nearest. 
LEONTODON ...| Section Apargidium, 1 | No common section or | Near 40 species of sec- 
species. species. tions distinct from the 
American. 
Connexions ...| Troximon, 16 species |... None nearer than Hypo- 
North-American, with cheris and Taraxacum. 
1 South-American spe- 
cies, besides Hypoche- 
ris and Taraxacum. 
TARAXACUM ...| None besides the com- | T. officinale (often colo- | About 5 species besides 
mon species. nist ?). the common one, Eu- 
ropso-Asiatic and Me- 
diterranean, the com- 
mon one cosmopolitan. 
Connexions | Leontodon. TE bon Paen, aega — and Chon- 
T . 
LACTUCA...:..... 8 species North-Ame- | Sections Cicerbita and | About 60 species, chiefly 
rican, of the two com- | Mulgedium, no com- Europzso-Asiatie and 
mon sections, and 1 or mon species. Mediterranean; the 
2 tropical-American. common sectionschiefly 
Europso-Asiatie, the 
Mediterranean often 
divergent, and a few 
tropical species. 
Connexions ... None nearer than Pre- |... sse Chondrilla and some 
nanthes, small genera, Europæo- 
Asiatic and Mediterra- 
nean. Prenanthes 
rather further. 
PRENANTHES ...| 10 North-American spe- | No common section or About 6 Europeo-Asiatic 
cies of a distinct (?) species. and Mediterranean spe- 
section. cies, near to but distinct 
from the American 
section. 
Connexions ...| Lactuca and Sonchus, not |............. eee Lactuca and Sonchus, not 
very near. very near. |. 
SONCHUS......... None besides the com- | S. oleraceus, L. (incl. S. | About 24 species, Euro- 
mon species. asper, Hoffm.), frequent | peeo-Asiatic and Medi- 
colonist. | terranean, including 
the common (cosmopo- 
| litan) species. 
Connexions ...| None nearer than Pre- |... Microrhynchus, Hetera- 
nanthes. chena, and Picridium 
about 27 species, chiefly 
Mediterranean. Pre- 
nanthes more distant. 
SCORZONERA | Pinaropappus, Lygodes- | No common genera. T jn aen ^ dg cron 
group. mia, Scorzonella, and d Tourecidid Vail 
Stephanomeria, about ola De y 
20 North-west Ame- ) species, Suropeo- 
rican, and Picrosia 1 Asiatic and Mediterra- 
South-American species. nosi.. 
Connexions ...| Cichoriaceæ poes. ES E AR n Cichoriacee generally. 
The above Table would appear to give ample evidence of a 
(geologically) modern interchange of Composite vegetation. 
Thirty of the thirty-eight generic groups have a general range 
over North-eastern Asia and Northern America, and may therefore 
be considered as comparatively continuous. They include about 
four-and-twenty species absolutely identical in the two divisions ; 
