ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



653 



Oxalate of Lime in Plants.* — Dr. A. Poli publishes a full account 

 of what is known respecting the occurrence of crystals of calcium 

 oxalate in plants, including a complete list of those species in 

 which they have been found, and a chapter on their physiological 

 value. 



Dr. Poli's own observations relate to species from a great number 

 of natural orders, but chiefly from Labiatae. The presence of calcium 

 oxalate is, he states, no characteristic feature of this class, several 

 genera being altogether deficient in it. When present, it occurs 

 in the greatest abundance in the rachis of the inflorescence. In 

 some species of Salvia the crystals appear to be suspended in the 

 cell-contents of the pith and cortical parenchyma, to be endowed with 

 Brownian movement, and to be accompanied by grains of chlorophyll 

 or starch. 



The clusters of crystals which occur in the extrafloral nectaries 

 of Ricinus are first formed in the nectaries at the base of the cotyle- 

 dons, around the vascular bundles. The young seedling has no 

 crystals of calcium oxalate within its tissue until it has attained a 

 height of nearly 0*1 m. and its cotyledons are fully developed. 

 There are no crystals in the male flowers of Bicinus. 



Insects and the Cross-fertilization of Flowers.t— Doubts have 

 been raised by H. Heckel and others, as to the role of insects in the 

 cross-fertilization of flowers ; based especially on their supposed 

 absence, or at least, their great rarity on the flowery summits of high 

 mountains. The results of four years' observations at Grenoble, by 

 C. Musset, at all altitudes from 200 m. to 3000 m., and amidst 

 one of the richest herbaceous floras in the world, are instructive. 

 He finds (1) that all orders of insects have representatives up to 

 2300 m. ; (2) that beyond 2300 m. Lepidoptera, Diptera, and certain 

 Hymenoptera preponderate in number ; (3) that the number of genera, 

 species, and individuals of nectar-loving insects is proportional to that 

 of the flowers, and is sometimes incalculable ; (4) that the hours of 

 sleep and waking of flowers, and those of insects, are synchronous ; 

 (5) that the apparent number of nectar-loving insects is proportional 

 to the number of their favourite flowers, and the state of the atmo- 

 sphere and sky. M. Musset concludes that, as flowers and insects are 

 never simultaneously wanting, the objection referred to against cross- 

 fertilization is not well founded. 



B. CRYPTOGAMIA. 



Muscineee. 



Classification of Sphagnaceae4 — G-. Limpricht explains more in 

 detail the use of the character derived from the relative position of 

 the chlorophyllaceous and the hyaline cells for the classification of 

 species of Sphagnum. 



* Poli, A., ' I cristalli di ossalato calcico nelle plante ' (2 pis.), Rome, 1882. 

 See Bot. Centralbl., x. (1882) p. 311. See also this Journal, ante, p. 597. 

 f Comptes Rendus. xcv. (1882). 



X Bot. Centralbl., x. (1882) pp. 214-22. See this Journal, ante, p. 79. 

 Ser. 2.— Vol. II. 2 Y 



