586 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
base of which the cone of growth is inserted during the winter ; they ter- 
minate in this bud, which bears bud-scales. The leaves always spring 
from between two neighbouring canals, and at an equal distance from 
each of them. The buds referred to are enveloped in lignified scales, 
which remain as a protection for several years. 
Muciferous and Resiniferous Cells in the Yew.* — M. L. Mangin 
has found, in the leaves of the yew, muciferous cells which differ from 
those known in other plants by the fact that they contain a mass of pro- 
toplasm, a nucleus, and grains of chlorophyll. They are especially 
abundant in the palisade-tissue. This distribution of resiniferous cells 
through the green parenchyme in the yew is associated with the absence 
of the resin-canals characteristic of other Conifers. 
Histology of Pontederia.j — Mr. E. M. Wilcox describes the his- 
tology of the stem of an aquatic Monocotyledon, Pontederia cordata. 
Among other features it is characterized by the presence, on each side 
of the closed fibrovascular bundles, of specialized cells containing starch. 
Mr. E. W. Olive if describes several other points in the histological 
structure of species of Pontederia and Heter anther a, including continuity 
of protoplasm from cell to cell in the stellate tissue of the stem of 
P. crassijpes. 
Parasitism of Epiphegus.§— Mr. H. Schrenk describes in detail the 
structure of Ejpiphegus virginiana , belonging to the Orobanchaceae, and 
that of the root of the beech, on which it is parasitic in the United States. 
The structure of the haustorium and its connection with the host are 
very comjdicated, a complete union taking place between the tissues of 
the two plants. 
Structure and Composition of Galls. |] — Herr M. Kiistenmacher 
compares the general structure of galls to that of fruits. The substances 
which they contain are, in general terms, the same. In the formation 
of galls the tissue first affected is the conducting tissue. The substances 
formed in the largest quantities are tannin, starch, and oxalates. Cellu- 
lose is also often stored up, and similar pigments are formed to those 
which are contained in petals. Galls are generally provided with 
crevices for the interchange of air, which originate from stomates. 
Root-tubercles of Leguminosse.^T — According to Mr. A. Schneider, 
the root-tubercles of the Leguminosae bear greater resemblance in 
anatomical structure to a stem than to a root ; they are developed exo- 
genously from a meristem, which surrounds the spots infected by the 
rhizobe ; the cork is formed from a true pliellogen. The nuclei in the 
tubercles of Phaseolus vulgaris attain a large size, and delicate prolonga- 
tions give them an amoeboid form ; they afterwards burst, and allow 
the escape of the nuclear substance, which mixes with the cytoplasm. 
* Bull. Soc. Bot. France, xl. (1894) pp. 313-6 (1 fig.). 
t Journ. Cincinnati Soc. Nat. Hist., xvi. (1893) pp. 100-4 (4 figs.). 
j Bot. Gazette, xix. (1894) pp. 178-84 (1 pi.). 
$ Proc. Amer. Micr. Soc., xv. (1894) pp. 91-128 (10 pis.). 
|| Jahrb. f. wiss. Bot. (Pringsheim), xxvi. (1894) pp. 82-185 (6 pis.). 
•j Amer. Naturalist, xxvii. (1893) pp. 782-92 (1 pi.}. Of. this Journal, 1893, p. 774. 
