442 
A CENSUS OF THE INDIAN POLYGONUMS. 
Section lX.~^Echinocaulon. 
r ^ 59 ) Polygonum perfoliatum Linn, 
( 6 0) Polygonum sagittatum Linn, 
( 6 1) Polygonun* strigosum R, Br. 
Section X.^Aconogon, 
Species with an extra-Indian distri- (6s) Polygonum alpinum All. 
bution • . . • . 39 (66) Polygonum paniculatum Bl. 
(74) Polygonum sibiricum Laxm. 
Section XL-^Hniaria, 
(77) Polygonum Convolvulus Linn. 
^ (78) Polygonum dumetorum Linn. 
Total number of North-West Himalaya species : 59, or 747 per cent. 
This sub-sub-area has much the largest Polygonum population, 
and has the largest number of endemic species. It is the only sub- 
sub-area which has all eleven sections represented, and from its number 
of species and sections may be considered as the Polygonum head-quar- 
ters. The great variety of climates which this sub-sub-area enjoys is no 
doubt one of the chief causes of this wealth of species. To quote 
from Hooker and Thomson’s essay, this sub-sub-area presents “ a very 
gradual transition from the flora of Nepal to that of the arid Afghan 
hills. This is the case equally in the tropical, temperate, and alpine 
zones of vegetation, and in the interior as well as in the exterior 
Himalaya. ” We find the species of the section Avicularia confined 
chiefly to the inner drier districts, while other sections are more irre- 
gularly distributed over all the districts with a preponderance in the 
moister. The other sub-sub-areas to which the sixteen species men, 
tioned above are distributed are entirely central or Eastern Himalayan, 
unless with the exception of the occurrence of that very doubtful variety 
Wightiana of Polygonum sphdsrocephalum in the Nilgiris. 
VII.— Nepal. 
Species endemic to the sub-sub-area 
No species. 
Section II.-^Eleutherosperma. 
(3) Polygonum filicaule Wall. 
Species distributed to other sub-sub- 
areas • . . . . • 
Section VI. — Bistorta. 
b* 4 (27) Polygonum adine Don. 
• 9 (28) Polygonum vaccinifolium Wall. 
Section Vlll.-^Cephalophilon. 
(50) Polygonum Wallichii Meisn. 
^ (51) Polygonum sphacrocephalum Wall. 
