ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
445 
cork ; they generally consist of yellowish spheres or masses, largely 
composed of readily fusible substances. 
Development of Sieve -tubes in Angiosperms.* — In the vine 
(especially near the root-tips) M. L. G. Chauveaud finds sieve-tubes 
which result from the transformation of procambial cells without 
septation, and consequently without the production of the so-called 
“ companion-cell.” They may lengthen to as much as 50 times their 
diameter. The indirect mode of formation of sieve-tubes is not there- 
fore, as has been stated, universally characteristic of Angiosperms as con- 
trasted with Gymnosperms. The author has observed the direct mode 
in several other instances. The two modes of development may even 
occur in the same bundle, as is the case with wheat. 
Structure and Arrangement of Laticiferous Tubes.f — Dr. 0. 
Chimani has studied this subject, especially in the case of those plants 
which yield gutta-percha and caoutchouk. The best staining reagent for 
the resin of the latex was found to be a solution of alkanna in acetic acid. 
Gutta-percha is yielded almost exclusively by plants belonging to 
the Sapotaceae ; caoutchouk by plants belonging to ihe natural orders 
Moracese (including Eiceae), Eupliorbiaceae, and Apocynaceae. The 
characters of a number ’ of species are described in detail, especially 
the dimensions of the laticiferous tubes. The tubes of the Sapotaceae 
are distinguished by their remarkably short segments ; but the septa 
are resorbed in the middle, leaving only a very thin membrane. The 
solid particles contained in them have a bone-shaped form. The tubes 
of those plants which yield caoutchouk are usually branched, but they 
never anastomose ; they are often segmented. They frequently have an 
elongated lens-shaped transverse section, due to partial obliteration ; 
this occurs especially in Landoljpliici (Apocynaceae). The medullary 
sheath exhibits peculiar large interruptions. The presence of latex was 
determined in the hairs of Castiloa clastica. 
Tanniferous Cysts in the Root.J — Dr. A. Pistone describes a 
peculiar structure which he finds in the radical cone of Phoenix dactylifera , 
causing tubercles which superficially resemble those of the roots of 
Leguminosae. It is due to the presence of cysts containing tannin ; 
this tannin is formed in the cell itself, and accumulates temporarily 
between the intercellular substance and the cell- wall. After a time one 
of the walls becomes invaginated, and the pocket thus formed constitutes 
a receptacle in which are formed spherical drops ; the substance of which 
they are composed remains in this form until it is required for the use 
of the plant. The membrane which surrounds these drops, and the 
peduncle which attaches them to the cell-wall, are composed of cellulose 
derived from the wall of the enclosing cell of which they form a part. 
Phloem-islands in the Xylem of Strychnos.§— M. E. Perrot has 
investigated the mode of formation of the phloem-islands in the xylem 
of the stem of Strychnos nux-vomica and of other species of the genus, 
* Comptes Eendus, cxx. (1895) pp. 165-7. 
t Bot. Centralbl., Ixi. (1895) pp. 305-13, 353-60, 385-94, 417-26, 449-61 (2 pis.). 
t Nuov. Giorn. Bot. Ital., ii. (1895) pp. 62-9. 
§ Journ. de Bot. (Morot), ix. (1895) pp. 90-5 (3 figs.); Bull. Soc. Bot. France 
xlii. (1895) pp. 209-12. 
1895 2 g 
