ZOOLOGY AND BOTAIIY, MICROSCOPY, ETC. 



987 



Orchide83, to serve as a storehouse for water. These structures attain 

 their largest development in Araucaria, where their branching gives them 

 a coral-like appearance. In the Cupressinefe of the southern hemisphere 

 they are altogether wanting. Northern representatives of those genera 

 which are most abundant south of the equator, display this structure to a 

 modified extent only. 



Swellings on the Roots of PapilionacesB.*— Herr A. Wigand gives a 

 resume of the extensive literature on this subject, and sums up in favour 

 of Brunchorst's view, that the so-called " bacteroids " are true bacteria. 



Root-tubers of Leguminosae.t — Herr A. Tschirch describes a pecu- 

 liarity in the structure of the digitate tubers in the root of Vicia sepium, 

 in which there is no suberous sheath to prevent the passage of the food- 

 material into the surrounding empty tissue. The same result is attained 

 by the separation of a layer of parenchymatous cells, which divide by 

 tangential walls into tabular cells, and the walls of these cells become 

 strongly suberized. 



Structure of Chenopodiaceae.J — From the examination of the compara- 

 tive anatomy of the stem and root of a large number of species of Chenopo- 

 diaceae, belonging to many different genera, Prof. St. Gheorghieff comes to 

 the following general conclusions : — 



The abnormalities in the stem and root are more frequent in the latter 

 than in the former, being often found in the root and not in the stem, but 

 never in the stem when they are not also in the root. They are especially 

 characteristic of perennial, and more particularly of climbing species, or of 

 the perennial parts, sometimes not making their appearance till the third or 

 even the fourth year. It is only rarely that neither stem nor root displays 

 abnormalities in its structure. The main point of the exceptional structure 

 is the large number of concentric secondary zones of increase in thickness, 

 and the separation of the phloem into separate bundles distributed over the 

 whole of the transverse section of the stem and the root. 



There are some species in which the peculiarities of structure are so 

 specialized that they can be distinguished from one another by the stem or 

 root only. This is the case with Haloxylon Ammodendron, Ealostachys 

 cas])ia, Grayia Sutherlandi, Suseda fruticosa, and Kocliia prostrata. 



A general review of the structure of the natural order is given, with 

 especial reference to the genera Bosea, KocJiia, Suseda, Halostachys, 

 Euroiia, Haloxylon, Hahlitzia, BoussingauUia, Basella, and Grayia. 



Biaxial Shoots of Carex.§ — While the mode of growth of the majority 

 of species of Cai-ex is a uniaxial sympodium, Herr A. Callme points out 

 that in two species, C. digitata and ornitJiopoda, the primary shoot remains 

 sterile, producing leaves only, while in its axis arise leafless and fertile 

 lateral shoots of the second order. 



Development of the Suckers of Thesium humifusum.|l— M. Leclerc 

 du Sablon states that the structure of the suckers of Thesium humifusum has 

 been studied with care by MM. Chatin and Solms-Laubach. Their develop- 

 ment has, however, not been followed. In the neighbourhood of the grow- 

 ing point of the root a slight swelling can sometimes be noticed, analogous 



* Wigand's Bot. Hefte, ii. (1887) pp. 88-97 (1 pi.)- Cf. this Journal, ante, p. 429. 



t SB. Gesell. Naturf. Freunde Berlin, April 19, 1887. See Bot. Centralbl., xxxi. 

 (1887) p. 224. Cf. this Journal, ante, p. 429. 



: Bot. Centralbl., xxx. (1887) pp. 117-21, 150-4, 183-7, 216-9, 245-9, 280-3, 

 328-30, 359-65, 369-80 ; xxxi. (1887) pp. 23-7, 53-7, 113-6, 151-4, 181-5, 214-8, 251-6 

 (4 pis.). i} Ber. Deutsch. Bot. Gesell., v. (1887) pp. 203-5. 



II Bull. Soc. Bot. France, xxxiv. (1887) pp. 217-21. 



