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REPORT ON BOTANY, MDCCCXLl : 
likewise the concretions in the leaves of Morus nigra, alba, 
and multicaulis ; those of Broussonetia papyrifera, Humulus 
Lupulus, and Cannabis sativa, are situated at the basis of the 
hair. These substances are generally found on the upper 
surface of the leaf, beneath the epidermis, at times on the lower 
surface, as, for instance, in the ordinary fig tree, more rarely 
on both sides at the edge, as in hemp. A large leaf of 
Broussonetia papyrifera, contained 134,000 concretions. 
Carbonate of lime is frequently met with between the cells of 
the parenchyma of the leaves and their nerves, in the channels 
of the petioles of the leaves, and of the stems ; it is also found 
under two forms in the leaves, one containing a juice so acid, 
that it would dissolve the carbonate of lime. The author is of 
opinion, that the deposit here takes place through the car- 
bonate of ammonia of the atmosphere. The oxalate of lime 
forms glands in the leaves and the stems of Cactus. E/aphides 
consist of a membrane, which is filled with oxalate of lime ; 
they develop themselves in cells, which consist of a special 
tissue, and contain a nitrogenous substance. Silica covers 
the membranes of the leaves of many plants, perhaps of all ; 
and is found also in the cells of the stems of the Gramineoe, 
Cliaracece, and Equisetacece ; also in the intercellular spaces, 
and likewise in the form of a spheroidal concretion, which is 
secreted by a tissue that developes itself in a cell. Chara 
translucens is incrusted with silica ; Chara vulgaris, in the 
same water, is found covered with carbonate of lime and 
silica , whilst Chara hispida has only carbonate of lime. 
SPERMATOZOA IN PLANTS. 
On the Anthers of Chara, and on the Animalcules in the 
same, by Gustav Thuret, Annal. d. Sc. Naturell. vol. xiv. 
p. 65. The so-called anthers of Chara, consist in their in- 
terior of a convolution of fibres, with partitions, in which the 
spermatozoa are situated. These fibres, in the young state, 
are only oval sacs, they then get partitions, and afterwards, 
frequently very rapidly, a nucleus is produced, which assumes 
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