188 
them. This hothouse flora, which does not differ greatly in 
character throughout Europe, has been examined casually by a 
hich have as yet not been observed elsewhere, are included. 
Observations of this kind having been extended over many years, 
it is not surprising that very few new forms have been met with 
at Kew. 
If compared with that of any other local British algal flora the 
following list will immediately be found to present one very 
striking character. is is the relative abundance of the blue- 
green forms (Cyanophyceae). The composition of the flora may 
be mentioned at once, so as to illustrate this feature :— 
p Gen. Spec. 
_ Hhodophyceae si wis aa = m» i 1 
$ ———— Ee ae ea ae re 5 10 
E 
$| Stephanokontae ... e e se in 1 6 
D 
E URN Eo us TU 46 78 
Akontae (Conjugatae) pA es oes A 14 52 
Cyanophyceae 2 c se e Jie 29 72 
Bacillariales ... iut a aes zm ce 28 67 
Flagellatae ... xem X a em Ps 6 8 
Total .-. svi ee EN 130 294 
RE EL ak Se a | 1 
I y phy titute nearly 25 per cent. 
of the entire flora, whereas in other algal floras the percentage is 
generally much less. We shall see immediately how this is to be 
accounted for. 
The algal flora of Kew Gardens may be said to be composed of 
three elements, although possibly the two latter should be included 
under one heading. They may be described as :— 
(i. The greenhouse-flora, consisting for the chief part of blue- 
green Algae. It is to the presence of this element that their 
kon It is possible that some of the Cyanophyceae found in the hothouses are 
