ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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of bifacial leaves. In some species the mechanico-conducting bundles 
are provided with mechanical elements on their outer side. Calcium 
oxalate is generally diffused through the leaves, but never in the form 
of raphides, except in the genera Tecojohilsea and Campynema, which 
should probably be excluded from the order. 
Anatomy of the Leaves of Sapotaceae.* * * § — Herr G. Hollo describes 
the structure of the epidermal cells, liypoderm, trichomes, stomates, 
vascular bundles, bundles of sclerenchyme, and laticiferous vessels, in 
the Sapotaceae. The family is characterized by the presence of two- 
armed unicellular hairs. The mesophyll is invariably permeated by 
laticiferous vessels which contain caoutchouc. The palisade-tissue, and 
sometimes also the spongy parenchyme, likewise contain particles of 
caoutchouc. 
Venation of Cycas.j — The venation of the leaves of Cycas and 
Stangeria differs from that of other Cycadeac ; and M. O. Lignier finds 
these two genera to agree more nearly with one another than has 
generally been supposed. In Cycas revoluta and circinalis a number 
of very fine vascular bundles run from the midrib to the margin of the 
leaflet, resembling the arrangement in Stangeria. The venation of these 
two genera approaches that of ferns, and is noteworthy from a phylo- 
genetic point^of view. 
Laticiferous Hairs of the Cichoriacese.J — Herr L. Kny states that 
hairs containing latex are widely distributed through the Cichoriaceae, 
and describes them in detail in the case of Lactuca Scariola. They form 
papillae on the involucre, and are in connection with the laticiferous system 
of the rest of the plant through a narrow canal at their base. 
Anatomy of Vellosiaceae.§ — Prof. E. Warming describes the ana- 
tomical structure of this South American natural order (twenty-three 
species of Vellosia , eight of Barbacenia). The texture and structure of 
the leaves are adapted to their universal xerophilous habit. In Vellosia 
the stem is clothed with a covering of roots which form a complete 
mantle round it. They do not break through the leaf-sheaths, but 
penetrate between them outside the bark, whence the author terms them 
“ inter-vaginal ” roots. 
Root-tubers.|| — Herr M. Drohnig describes the structure of the root- 
tubers in a large number of species of Dicotyledons and some of Mono- 
cotyledons. In Ficaria ranunculoides , Tradescantia crassifolia, and 
Echeandia their formation depends on an excessive development of the 
cortical parenchyme, no pericambial cork being formed, and in some 
cases not even a phellogen. In (Enanthe and Aconitum their origin is 
from a secondary growth of the central cylinder of the root. In Oxalis , 
* ‘ Ueb. d. anatom. Bau d. Blattes in d. Sapotaceen u.s.w.,’ 59 pp. and 1 pi., 
Miinchen, 1892. See Bot. Centralbl., lvi. (1893) p. 334. 
f Bull. Soc. Linn. Normandie, 1893, 7 pp. See Bot. Centralbl., lvi. (1893) p. 151. 
% SB. Gesell. Naturf. Freunde Berlin, July 18, 1893. See Bot. Centralbl., lvi. 
(1893) p. 392. 
§ Overs. K. Danske Yidensk. Selsk. Forkandl., 1893, 44 pp. and 15 figs. See 
Bot. Centralbl., lvi. (1893) p. 94. 
|| ‘ Beitr. z. Kenntn. d. Wurzel-knollen,’ 80 pp., Breslau, 1892. See Bot. Cen- 
tralbl., lvi. (1893) p. 89. 
