ZOOLOQY AND BOTANY, MICROSCOPY, ETC. 
365 
with spiral pliyllotaxis ; in the former the growing-point is usually flat ; 
in the latter it is more or less conical ; the axillary buds are far more 
highly developed in the latter case than in the former. 
Stem of Grasses.* * * § — With respect to the comparative anatomy of 
their stem, Herr F. Hohenauer classifies grasses into three groups, 
viz. : — (1) With solid stem ; this includes only a few species, e. g. Zea 
Mays, Saccharum officinarum ; (2) an intermediate type, e. g. Bambusa 
stricta ; and (3) with hollow stem. This last group includes by far the 
largest number of species, which may again be divided into those in 
which the strengthening sheath is continuous, and those in which it is 
interrupted. 
In most grasses the stomates are arranged in rows, and present the 
appearance of having four guard-cells. A strengthening sheath is always 
present, and its cells are often lignified. Assimilating tissue sometimes 
occurs between this sclerenchymatous ring and the epiderm. The vas- 
cular bundles are always enclosed in a sheath, which is often lignified. 
The phloem always occupies the outer part of the bundle ; the vessels 
are annular, spiral, or pitted. The distribution of the bundles on a 
transverse section varies in different species. 
Knees of Taxodium distichum.| — Dr. J. P. Lotsy describes the 
formation and histological structure of the remarkable processes which 
grow from the roots of this tree only when growing in swampy situations. 
Morphologically the knee is a limited local hypertrophy on the upper 
side of the curve of a root springing from the base of the stem and 
running near the surface of the soil. When young the cells of the knee 
contain abundance of the spores of a fungus probably belonging to the 
Ustilaginese. The author was unable to come to any definite conclusion 
as to the function of these structures. 
Blind Root-suckers of Swamp-forests.J — Mr. R. L. Heinig describes 
the contrivances by which the trees which constitute the forests in a 
swampy portion of the Ganges Delta are enabled to resist the uprooting 
effects of storms. One of the most important of these is the develop- 
ment of blind root-suckers, which are found in species of Avicennia, 
Sonneratia, and other genera, and especially in Heritiera fomes. They 
are woody processes, growing in an upward direction, and developed at 
irregular distances along the whole course of the roots. They project 
from 1 to 3 feet above the surface of the ground, and apparently cease 
to grow when the apex has reached the level of the highest spring tides. 
They are destitute of buds, and are incapable of producing them ; but 
are abundantly supplied with cavities for the aeration of the root. 
Succulent Composit9e.§ — Herr J. Muller describes the peculiarities 
of the structure of a number of species of succulent Composite, chiefly 
belonging to the genera Kleinia, Sonchus, Senecio , and Othonna, the 
succulence being manifested sometimes in the stem, sometimes in the 
* Abhandl. Zool.-bot. Gesell. Wien, xliii. (1893) pp. 552-68. 
f Studies Biol. Lab. Johns-Hopkins Univ., v. (1893) pp. 269-77 (2 pis. and 
3 figs.). Cf. this Journal, 1890, p. 626. 
1 Journ. Asiatic Soc. Bengal, Jxii. (1893) pp. 158-61 (1 pi.). 
§ ‘Beitr. z. Anat. holziger u. succulenter Compositen,’ Berlin, 1893, 42 pp. and 
4 pis. See Bot. Centralbl., lvii. (1894) p. 53. 
