INTRODUCTION 
XXXI 
partly accounted for by the fact that a small portion of the former 
comes within the subtropical zone. Apart from this, the British 
flora is very poor as compared with the Japanese, for example, even 
after eliminating the subtropical element found in the warmer 
part of J apan. Again, comparing the list of Orders not represented 
in Britain with the list of Orders represented in Simla by only one 
genus and one species it will be seen that sixteen out of twenty- 
three are the same. Among Orders which do not occur in Britain 
several which are not wholly tropical or subtropical are somewhat 
numerous in Simla. Thus of the Butaceae there are seven genera 
and seven species, of the Asclepiadaceae ten and fourteen, and of 
the Acanthaceae ten and fifteen, respectively. 
Against this, twelve Natural Orders are represented in the 
British flora but not in that of Simla. About half of these, how- 
ever, are aquatic or marsh plants, which accounts for their absence 
from Simla. The rest are small Orders, except the Amaryllidaceae, 
of which the Haemodoraceae and Hypoxidacese are regarded as 
Suborders by some botanists. 
Natural Orders represented in the Simla District but not in 
the British Islands. 
Magnoliaceae 
Menispermaceae 
Capparidacese 
Bixaceae 
Malpighiaceae 
Butaceae * 
Simarubaceae 
Meliaceae 
Vitaceae 
Sabiaceae 
Anacardiaceae 
Coriariaceae 
Myrtaceae 
Melastomaceae 
Samydaceae 
Begoniaceae 
Datiscaceae 
Ficoideae 
Myrsinaceae 
Styracaceae 
Asclepiadaceae 
Loganiaceae 
Gesneraceae 
Bignoniaceae 
Acanthaceae 
Nyctaginaceae 
Amarantaceae 
Phytolaccaceae 
Piperaceae 
Lauraceae 
Balanophoraceae 
Juglandaceae 
Gnetaceae 
Scitamineae 
Haemodoraceae 
Hypoxidaceae 
Dioscoreaceae 
Commelinaceae 
Natural Orders represented in the British Islands but not in the 
Simla District. 
Nymphaeaceae 
Besedac eae 
Cistaceae 
Frankeniaceae 
Portulacaceae 
Elatinaceae 
Empetraceae 
Polemoniaceae 
I Ceratophyllaceae 
Hydrocharidaceae 
Amaryllidaceae 
Typhaceae 
