ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
215 
rose, violet, tuberose, orango). Ho finds that the essential oil is usually 
present in the epidermal cells of the upper surface of the petals and 
sepals, but it may also occur on both surfaces. The oil appears, in all 
cases, to originate in the chlorophyll, and to be a product of its trans- 
formation. The production of the perfume is, to a certain extent, in 
inverse ratio to that of tannin and of the floral pigments ; and it is not 
fully manifested until the essential oil is sufficiently freed from the 
intermediate products of transformation. It follows that green flowers 
are seldom scented ; while the Composite, which are exceptionally rich 
in tannin, have commonly a disagreeable odour. 
Frank’s Text-Book of Botany.* * * § — The first volume of this work — a 
re-issue of Sachs’s ‘ Lehrbuch ’ enlarged and adapted to the present state 
of knowledge — deals exhaustively with the structure of the cell, and the 
general phenomena of anatomy and physiology. Special attention is 
paid to those branches in which the author has carried on personal 
investigation, such as the absorption of free nitrogen by plants and 
fungus-symbiosis. 
B. CRYPTOGrAMIA 
Cryptogamia Vascularia. 
Grleicheniacese.f — M. G. Poirault has investigated the anatomical 
structure of the genera GleicJienia , Platyzoma, Mertensia , and Stromato- 
pteris ; that of Platyzoma differs considerably from the normal. All the 
species of the subgenus Eugleichenia, with one exception, have, in the 
pericycle of their petiole, punctated or reticulate cells with strongly 
lignified walls ; these cells are connected with a sclerenchymatous tissue 
which occupies the centre of the petiole. They are usually absent from 
the stem. In Mertensia they are either isolated or are entirely wanting. 
In the central sclerencliyme is a fusiform deposit of brown non-lignified 
but very hard cells, surrounded by a layer of cells with lignified frame- 
work, the endoderm of authors. In the stem or petiole of certain species 
of GleicJienia , some of the sieve-tubes are clothed on the inside with a 
lignified deposit. The structure of these sieve-tubes resembles that of 
other ferns. 
Leaves of Annularia.| — From an examination of fresh material, 
Herr H. Potonie is able to confirm the accepted view that the leaves of 
Annularia stellata must be regarded as the foliage of a plant belonging 
to the Calamites or Equisetaceae. The differences are only slight 
between the leaves of Annularia stellata , of Equisetites zeseformis , and of 
Calamites varians. 
Muscinese. 
Classification of Mosses.§ — Prof. C. E. Barnes publishes an analytical 
key to the genera and species of Musci (Sphagnaceae, Andreaeaceae, 
Archidiaceae, and Bryaceae) found in North America. 
* ‘ Lehrbuch d. Botanik nach d. gegenwartigen Stand d. Wissenschaft. Band I. : 
Zellenlehre, Anatomie, u. Physiologic,’ Leipzig, 1892, 227 figs. See Bot. Central bl., 
lii. (1892) p. 250. f Comptes Rendus, cxv, (1892) pp. 1100-3. 
X Ber. Deutsch. Bot. Gesell., x. (1892) pp. 561-8(1 fig.). 
§ Trans. Wisconsin Acad. Sci., viii. (1892) pp. 11-81, 163-6. 
