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 J apanese, for example, even 
after eliminating the subtropical element found in the warmer 
part of Japan. 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 Rutacese there are seven genera 
and seven species, of the Aselepiadaceae 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 Amaryllidacese, 
of which the Hsemodoraceae and Hypoxidaceae are regarded as 
Suborders by some botanists. 
Natural Orders represented in the Simla District but not in the 
Magnoliaceae 
British Islands. 
Melastomaceae 
Amarantaceae 
Menispermaceae 
Samydaceae 
Phytolaccaceae 
Capparidaceae 
Begoniaceae 
Piperaceae 
Bixaceae 
Datiscaceae 
Lauraceae 
Malpighiaceae 
Ficoideae 
Balanophoracese 
Rutaceae 
Myrsinaceae 
Juglandaceae 
Simarubaceae 
Styracaceae 
Gnetaceae 
Meliaceae 
Asclepiadaceae 
Scitamineae 
Vitaceae 
Loganiaceae 
Haemodoraceae 
Sabiaceae 
Gesneraceae 
Hypoxidaceae 
Anacardiaceae 
Bignoniaceae 
Dioscoreaceae 
Coriariaceae 
Acanthaceae 
Commelinaceae 
Myrtaceae 
Nyctaginaceae 
Natural Orders represented in the British Islands but not in the 
Simla District, 
Nymphseaceae 
Resedaceae 
Cistaceae 
Frankeniaceae 
Portulacaceae 
Elatinaceae 
Empetraceae 
Polemoniaceae 
Ceratophyllaceae 
Plydrocharidaceae 
Amaryllidaceae 
Typhaceae 
