184 The Botanical Gazette. [May, 
ning from the mass into each ray of the cell. In many cases 
the thread held fast through the pore to that of the adjoining 
cell—a beautiful exposition of continuity of protoplasm. 
The presence of active nuclei in the cells of the diaphragm 
and of starch in some, and the continuity of the protoplasm 
in the cells, is suggestive of these cross-plates serving a far 
more important function than the mere mechanical one of 
support. These facts indicate rather a close connection with 
the centers of vital activity in the plant. 
New light may be thrown by such a suggestion upon the 
presence and regular occurrence of diaphragms in this group 
of plants. Some physiological experiments may further 
point out the real functions. It is expected that a careful 
study will be made of the structure of plants of allied groups 
and the true relationships of aquatics sought. 
BIBLIOGRAPHY. 
.Du UVAL Jouve, Diapvh ieZ uatiques 
3 vo TieGuem, Ann. Sci. Nat., V. 6: 132. édons. 
M. Trevs, Le méristéme primitif de la racine dans les monocotyl 
Musée Bot. ae Leide, 1876 orence, 
5. F. ParLatorg, Tavole = una anatomia delle piante aquatische. Fl 
1881. Published by T. Car 1883. 
6. F. aie EBRAND, Ber ichte ie Dounebek Bot. Gesell. 1: xxvit—XxIX. lin- 
7 a i Rnshierches sur = péricyclus ou seri périphérique es 
~ central chez les phanérogames. Ann. Sci. Nat., VI. 20: eh atc ® riace® 
S. ONLAND, The apical ctletain in the roots of the Pontede 
pak. of Bot i 179- 182, 1885. 0. = 
. S. Scudnianp, Engler and Prantl, Nat. PAanzenfam., II. Abth.4. 7 
To, i. Petrr, Nouvelles recherches sur le pétiole des phanérogames. 
S. L. Bordeaux—: I-50. 1889. data, Jout. 
It. E, M. Wincox, The nate Oey of the stem of Pontederia cordata, 
Cincinnati Soc. of Nat. , July—Oct., 1893. 
Wabash College, Cradle Ind. 
ExpPLANATION OF PLaTEe XVII. 
—Fig. *. 
Fig. 1. A young plant of ee — showing an off-shoot. X aioe 
Transection of ro ot of P. cras . *140,—Fig. 3. Lon ngisection fro P 
7. f fe of Pe cordata. Upper portion 0 
the large ¢ cel S among the palisade calla, the former filled wit 
350. 
