ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 705 
with starch in winter. Great abnormalities are presented by some genera 
of conifers. 
Fruit-bearing Axis of Palms.* — M. H. Micheels has studied the 
structure of the axis which bears the fructification in 32 species and 
varieties belonging to 19 genera of palms. The following are the more 
important results. Every vascular bundle is completely enclosed in a 
sclerenchymatous sheath. The xylem usually contains a few vessels of 
remarkably large size. In some species the bundles are free, and im- 
bedded in a homogeneous or irregular fundamental tissue. In other 
species the inner bundles are the largest, and are united by their scleren- 
chyma-sheath into a more or less uninterrupted ring. In others again, 
all the bundles unite, by the coalescence of their phloem portion, into a 
central string with larger or smaller interstices. 
Anatomy of the Stem of Thunbergia.’}’ — While many species of 
this genus exhibit a normal structure of the stem, others present abnor- 
malities in various directions. These are described by M. C. Roulet, 
especially the anatomical peculiarities of the section Hexacentris. Two 
parallel elongated leptome-islands occur here in the xylem, in vertical 
lines corresponding to furrows in the stem. The alternating zones of 
leptome and hadrome are caused by the cambium giving off alternately 
xylem and phloem on its inner side. 
(4) Structure of Org-ans. 
Bright Colour of Alpine Flowers 4 — Dr. J. Joly adduces numerous 
instances in which the flowers of Alpine plants are more brightly 
coloured than those of the same species growing at low'er altitudes. He 
attributes this primarily to the scarcity of pollinating insects at high 
altitudes, only those individual plants surviving, in the struggle for 
existence, which are especially endowed, from the size or brightness of 
their flower, with the power of attracting insects. Large numbers of 
insects appear to perish from cold on the higher Alps, being attracted 
in the dusk by the light from the snow. 
Extra-floral Nectaries of Aleurites.§ — Mr. P. Groom has examined 
the structure of the nectaries which are found on the petiole of special 
unlobed leaves of Aleurites cordata belonging to the Euphorbiacese, with 
relation to the question whether the laticiferous tubes contain carbo- 
hydrates or not. He finds only a very slight connection between these 
tubes and the secreting cells of the nectary. 
Self-adaptation of Plants to their Environment. |] — Rev. G. Henslow 
gives a variety of exemplifications of the special characters of desert 
plants, drawn from the flora of Egypt, arranged under the following 
heads : — General Morphological Characters ; Spinescent Characters ; 
Foliage ; Succulent Plants ; Protection of Buds ; Roots ; Histological 
Peculiarities ; Assimilating Tissues ; Ligneous Tissues ; Water-storage 
* Mem. Acad. R. Sci. Belgique, liii., 52 pp. and 1 pi. See Bot. Centralbl., lix. 
(1894) p. 186. 
f Bull. Herb. Boissier, i. (1894) p. 259 (1 fig.), See Bot. Centralbl., lix. (1894) 
p. 369. t Scient. Proc. R. Dublin Soc., viii. (1893) pp. 145-53 (1 tig.). 
I § Ann. Bot., viii. (1894) pp. 228-30. 
|| Journ. Linn. Soc. (Bot.), xxx. (1894) pp. 218-63 (1 pi.). 
