1 68 
Notes . 
passing over the upper surface of the leaf. Other experiments on the 
respiration of rejected leaves support the view that the stomatal 
openings, in spite of their minuteness, offer a very much easier path 
from the atmosphere to the interior of the leaf than does the cuticle. 
Conclusions . — i. Under normal conditions practically the sole path- 
way for C0 2 into or out of the leaf is by the stomata. Since oxygen 
diffuses more readily than C0 2 through fine openings, the same probably 
holds for oxygen and the whole of the gas-exchange. 
2. Under abnormal conditions, when the stomata or intercellular 
spaces are blocked and the surrounding tension of C0 2 is great 
enough, passage of C0 2 by osmosis through the cuticle may take 
place. 
3. That such closure of stomata as is held to take place in darkness 
does not prevent the distribution of gas-exchange closely agreeing 
with that of the stomata. 
4. That the exhalation of C0 2 in bright light by a leafy shoot in 
Garreau’s well-known experiment is not the expression of any phy- 
siological truth, but only due to the imperfections of the conditions. 
Isolated green leaves fully illuminated allow no C0 2 to escape from 
them. 
SOME NEW BRITISH ALGAE.— While collecting at Weymouth 
in September, 1892, 1 found some Algae which do not appear to have 
been previously described. Full descriptions and figures of these will 
appear in an early number of the Annals of Botany. In the meantime, 
as I have distributed specimens of the plants amongst my friends 
under manuscript names, it may not be out of place to give very short 
descriptions of them now. 
Among the most interesting was a little epiphyte on Castagnea 
Griffithsiana , J. Ag., which proved to be the type of a new genus which 
I have called after my friend Mr. T. H. Buffham. 
The genus Buffhamia belongs to the Chordariaceae, and may be 
described as follows: Fronds simple, cylindrical, solid, composed of 
an inner layer of large angular-roundish colourless cells and a cortical 
layer of closely-packed small coloured cells, from which at maturity 
arise short, jointed assimilating filaments (paraphyses), plurilocular 
sporangia and colourless hairs. Plurilocular sporangia, the only form 
of reproductive organs at present known, linear-oblong with obtuse or 
slightly pointed apices, stalked. 
