462 MR. H, B. GUPPY : PLANT-DISTRIBUTION 
in both worlds. This gives a total of 106 both-world families out of a total of 
153 mainly or exclusively tropical families, or 69 per cent. 
The total of 62 families exclusively or mainly extra-tropical in the 
northern hemisphere is made up of 36 exclusively north temperate and 
26 north temperate and tropical but mainly north temperate. Of the 
exclusively north temperate 23 and of the mainly north temperate families 
25 exist in both the Old and the New Worlds. This gives a total of 
48 both-world families out of a total of 62 northern extra-tropical families, 
or 77 per cent. 
It is worth noting the manner in which, according to these results, the 
both-world families tend to congregate in the intermediate region between 
the tropies and the north temperate zone—that is, among the tropical and 
north temperate families that are mainly tropical and among the north 
temperate and tropical families that are mainly north temperate. Con- 
siderable importance attaches itself to the interpretation of this tendency. 
TaBLE I. 
(See Explanatory remarks.) 
A.—The distribution of the Angiosperms between the Old and New World. 
Primaries. Cohorts. Families. Tribes. Genera. Species. 
No.| °/, |No.! h [No] % |No.! % | No. | % | No. | %, | 
|— DB ESS RSR S R " | PEOS | 
|! Old World 2, 45, 45| 165 | 39! 94:5 | 570 | 46| 9889| 52 
New World....| .. | .. | 2 45.) 35| 190 | 31| 19:5 | 519 | 41| 8874. 47 
Both Worlds .. .. 100 41 9L0 192 705 80 560 168 13 197 1 
6 100 45 100 272 100 159 100 1259 100 18060 100. 
B.—Composite excluded. 
Tribes. Genera, Species. 
| N o " A No s. Né 0 
| NERE OE mU 
Old World .......... 38 26 970 | 51 5031 52:6 
New World ........ 3 21 Noi op g9 4411 46:0 
Both Worlds ........ 77 53 B0 be T 134 l4 
146 100 539 | 100 9576 100 — 
