168 
MERRILL. 
Table I . — Summary of the families, genera, species, etc. — Continued. 
Families and genera. 
1 Total species. 
1 Indigenous. I 
Intro- 
duced. 
Endemic. 
Ameri- 
can 
origin. 
Pan tro- 
pic: Dis- 
tributed- 
j 
To Australia. 
To Polynesia. | 
< 
H 
Spontaneous. 
Cultivated only. 
Spontaneous. 
Cultivated only. 
By natural agen- 
cies. 
j Through agency 
of man. 
1 To Malaya. 
To tropical Asia. 
Compositae; 
1 
1 
2 
2 
2 
2 
J 
J 
J 
1 
1 
1 
J 
1 
1 
1 
Emilia 
1 
1 
1 
1 Elephantopus 
3 
3 
3 
3 
1 
1 
2 
1 
I Sphaeranthus . 
1 
1 
1 
1 
1 
Blumea 
4 
2 
2 
3 
1 
1 
1 Pluchea . 
1 
1 
1 
1 
Grangrea 
1 
1 
1 
1 
1 
Crossostephium 
1 
1 
Synedrella 
1 
1 
1 
1 
1 
1 
1 
1 
1 
Artemisia __ _ 
1 
1 
1 
1 
1 
1 
Epaltes 
1 
1 
1 
1 
Centipeda 
j 
1 
Erigeron 
1 
1 
J 
1 
J 
Tagetes 
1 
1 
1 
1 
1 
1 
Chrysanthemum 
3 
3 
3 
2 
2 
Enhydra 
1 
1 
1 
Eclipta 
2 
2 
2 
\ 
J 
Helianthus 
1 
1 
Wedelia 
2 
2 
J 
J 
Cosmos 
j 
1 
\ 
1 
Bidens 
1 
1 
1 
j 
1 
1 1 
Lactuca 
1 
1 
1 
j 
\ 
1 
J 
1 
Sonchus 
1 
j 
1 
1 
1 1 
1 
1 
J 
Totals 
1,007 
550 
232 
225 
124 
83 
95 
89 ! 223 
812 
789 1 
425 
355 
402 
The introduced element in a flora is not frequently treated as 
such, although the subject is a fascinating one in many respects. 
Investigation of the subject involves not only an extensive 
knowledge of the flora of the region under discussion, but also 
detailed information as to the nature of the plants, their relative 
abundance or rarity, their habitats, their native names, special 
methods by which their seeds may have been disseminated, 
ancient and modern trade routes, and other factors. In the 
case of a species suspected of having been introduced it is desir- 
able that its original home be determined as nearly as possible. 
This involves a study not only of the plant itself, but of its 
allied forms and their recorded ranges, and especially a study 
