1896. | Anatomical and Physiological Researches. 33 
countries there are modifications, according to the author, 
‘that only become comprehensible to us when we sufficiently 
value the great importance of transpiration.” 
The first of these is the spongy parenchyma, which is es- 
pecially fully developed in plants growing in moist, shady 
places and in the dampest tropical countries. The many 
branched cells, bordering on large intercellular spaces, facili- 
tate evaporation. Polypodium setigerum is a good example 
of a tropical plant of this kind. It is made up almost entirely 
of spongy parenchyma, bordering on very large intercellular 
spaces. 
In his article on rain fall and the shape of leaves,!! Stahl 
concludes that the principal use of the draining of the leaf 
surface was to promote transpiration. The author promises 
another paper containing more complete discussion of the 
adaptations for transpiration. 
In this connection I will call attention to what Dr. H. 
Schenck!? has to say in regard to the development of spongy 
parenchyma in shade and especially in water plants. He 
does not consider it in any way as a means of facilitating 
transpiration, but on account of the less intense light it is 
necessary in order to increase the surface as well as the num- 
ber of working cells which may be exposed to CO,. This 
latter view it seems to me is most probably the true one. 
_Although Stahl holds firmly to the notion that transpira- 
tion is of great physiological value to the plant, yet the facts 
which he has observed may be readily interpreted the other 
way. In spite of some uncomplimentary things which have 
been said about this paper by a foreign reviewer, *® it is one 
of the most suggestive and helpful articles on transpiration 
which has appeared for several years.—ALBERT F. Woops. 
B “’Stahl, E., Regenfall und Blattgestalt. Annales du jardin botanique de 
uitenzorg 11; 98-182, p/. 5-12. 1893. 
137° Biologie der Wassergewachse 7-9. Bonn, 1886. 
Jensen, H., Botan. Litteraturblade —: 149-152. 1894. [Copenhagen. ] 
3—Vol. XXI.—No. 1 
