ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



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contained only bordered, and 34 only simple pores ; the remaining 7 

 varying in their different genera. The author considers it probable that 

 there is a decided difference in function between simple and bordered 

 pores, the latter having more especially for their object to facilitate the 

 passage of water through the plant. With extremely few exceptions, 

 when the libriform cells are used as reservoirs of starch, this substance 

 is formed only in those with simple pores. 



Albumen-vessels in the Cruciferae and allied orders.* — Herr E. 

 Heinricher finds the peculiar idioblasts already described by him in 

 species belonging to 18 out of the 21 tribes of the order CruciferaB. 

 Their distribution in the various points of the plant differs in different 

 species. In Capparidese they were found in three species of Capjjciris, 

 but not in Cleome ; in the Papaveracefe, in EscJischoltzia ; in the 

 Fumariaceee, in Adlumia and Corydalis. The micro-chemical reactions 

 showed the contents of these tubes to be always of an albuminoid character. 

 The hypothesis that they are not simply reserve-organs, but that the 

 proteids are formed in them, is rendered highly probable by the sharj) 

 localization of their contents, which are well differentiated from the 

 protoplasm of the surrounding cells. They are apparently first formed 

 at a very early period, their rudiments being visible even in the ripe 

 cotyledons of the seeds of Sinapis alba. Phylogenetically the author 

 adopts the view that they are derived from the segmented laticiferous 

 vessels of the Papaveracese. In Adlumia and Corydalis these albumen- 

 vessels are very long, and form a reticulation in the mesophyll of the 

 leaf similar to the laticiferous vessels of EiqoTiorbia ; but they have blind 

 endings. 



Tannin-receptacles in the Fumariacese.t — Herr W. Zopf describes 

 structures in the Fumariacese, which appear to correspond to the latex- 

 tubes in the allied order Papaveraceae. He finds them in all species 

 examined of the genera Corydalis, Adlumia, Dicentra, and Fumaria, and 

 in all parts both above and under ground. They take the form of 

 idioblasts, very often of great length but undivided, containing a colour- 

 less, red, or yellow substance of the nature of tannin. They are either 

 protogenous, formed in the primary meristem, or hysterogenous, developed 

 in the cortex or cambium of the vascular bundles. In both cases they do 

 not at first differ from the ordinary cells. No fusion of cells nor sieve- 

 plate-structure was observed. A nucleus was in all cases detected, and 

 in the longer idioblasts there are probably several. 



These receptacles contain large quantities of tannin, either colourless 

 or coloured by a yellow or red anthocyan, the latter especially in those 

 parts which are exposed to strong light ; and this is apparently the result 

 of the action of vegetable acids. The yellow pigment is also formed in 

 the course of development of the plant, and is preceded by a colourless 

 substance or chromogen. There are probably a . number of different 

 anthocyans characteristic of different plants. 



Formation of Cork in the Stem of plants with few or no leaves. | — 

 Herr H. Eoss has investigated the structure of the stem in relation to 

 the development of cork in a number of plants in which the stem is 

 nearly or quite leafless. He finds that in such plants, where the stem 

 is perennial, assimilating tissue is always formed in the outer cortex, and 



* MT. Bot. lust. Graz, i. (1886) pp. 1-92 (3 pis.). Cf. this Journal, 1885, p. 672. 

 t Bibliotb. Bot., 1886, 42 pp. and 3 pl.s. See Bot. Centralbl., sxix. (1887) p. 39. 

 1 Ber. Dentsch. Bot. Gesell., iv. (1886) pp. 362-9. 



2 F 2 



