ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
471 
Cystoliths of Coccinia. * — Sig. C. Avetta describes the cystolitbs 
found in the leaves of some species of this genus of Cucurbitacem. 
Unlike those of Momorclica, they occur only in the epiderm of the upper 
surface. When mature they completely fill up the cavities of their 
mother-cells ; they are inserted, not on the outer wall of the epidermal 
cells, but at the edges of the cells which form the centre of each group. 
Anatomy of Rubiaceae.f — Herr H. Solereder describes in detail 
the anatomical structure of this order, and makes several suggestions 
with regard to the systematic position of the genera. The most in- 
variable characters are the presence of two or more auxiliary cells 
accompanying the guard-cells of the stomates ; the absence of glandular 
hairs on the leaves ; and the invariably simple collateral vascular bundle 
in the axis. In Pavetta and Strumpfia , crystals arise in the cells of the 
pith, liber, and primary cortex of the stem, which become surrounded by 
a wall of cellulose, and finally constitute a peculiar sclerenchymatous 
tissue. Cystoliths were not detected in any species of Rubiaceae. 
7 (4) Structure of Organs. 
Variety and Localisation of Organs as Evidence of Gradation.^ — 
According to M. A. Chatin, a variety or multiplicity of organs, as con- 
trasted with a multiplicity of homologous parts, is a sign of elevation 
of structure. Various degrees of degradation are exhibited by parasites, 
by aquatic plants, and by those in which one of the floral envelopes 
is suppressed. The presence of endosperm in the seed is evidence, 
not of high, but of low organization, since it indicates an arrest of 
development, those processes being delayed till after germination 
which, in exalbuminous seeds, are completed before germination. 
Dicotyledons exhibit, in many points, a greater differentiation of 
organs than Monocotyledons, and are, therefore, higher in the scale. 
Thus the primary root of Monocotyledons is generally arrested in its 
development ; and this is still further the case in Vascular Cryptogams ; 
the stem of Monocotyledons is much less branched, and has no strongly 
differentiated pith, pericycle, or endoderm ; the leaves are not usually 
stalked. The author places the Gamopetalm with superior ovary at the 
head of the various divisions of the vegetable kingdom. 
Hermaphroditism must, by the same law, be treated as a higher 
type of structure than unisexuality ; and this occurs most universally 
in the Gamopetals© with superior ovary. 
Young Form of Gymnosperms.§ — Dr. H. Schenck notes that, in 
many Coniferse and some Cycadem, the young plant differs in biological 
characters from the mature plant. In the larch this is especially shown 
in the fact that, during the first four years at least, a portion of the 
* Ann. R. 1st. Bot. Roma, v. pp. 181-4. See Morot’s Journ. de But., 1893, Rev. 
Bibl., p. ci. 
t Bull. Herb. Bois3ier, i. (1893) pp. 167-83, 268-86, 308-26. See Bot. Centralbl., 
1894, Beih., p. 26. 
% Comptes Rendus, cxvii. (1893) pp. 604-7 ; cxviii. (1894) pp. 773-7 ; and Bull. 
Soc. Bot. France, xl. (1893) pp. 328-30; xli. (1894) pp. 217-23. Cf. this Journal, 
1893, p. 754. 
§ SB. Niederrhein. Gesell. Naturk. u. Heilk. Bonn, 1. (1893) pp. 27-38 (5 figs.). 
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