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JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



epidermis are common. An endodermis separated the cortex from the 

 mechanical cylinder, which latter consists of from one to five layers of 

 close-set, strongly-thickened, rounded cells. This mechanical cylinder is 

 nearly continuous, and is only interrupted at the nodes. 



The vascular bundles (probably collateral) are usually united to form 

 a ring. The perennial species show distinct annual rings in the wood, 

 which in these cases is interrupted (see above). The leaves are very 

 primitive in structure. There is no distinct difference in the shapes of 

 palisade and spongy cells respectively ; there is a mass of collenchyma or 

 sclerenchyma above the collateral bundles, which is enclosed with them in 

 a bundle-sheath. The stipules develop from a very small, many-layered, 

 basal part, and eventally become dry, silvery-white, and one-layered. The 

 following specific differences are noted : — 



(1) Isolated vascular bundles in Spergula, Corrigiola, and Pycnophyl- 

 lum. (2) No mechanical ring in Drymaria and Pycnophyllum. (3) 

 Hard-bast only in Lceflingia. (4) Lignified cork-cells in Spergula root. 

 (5) Lignified cortex-cells in Drymaria. (6) Lignified pith-cells in Sjjlicero- 

 coma, Pollichia, and Gymnocarpos. (7) Companion-cells to stomata, 

 Siphonychia. (8) Gland in place of stipules, Ortega. — G. F. S.-E. 



Starch and Inulin. 



Starch and Inulin (Beih. Bot. Cent. bd. xii. ht. 2, pp. 226-212).— 

 This paper has been written by Hugo Fischer in reply to a reference by 

 Correns on the author's well-known article on Inulin. It is mainly a 

 criticism of Niigeli's theory. The author has repeated Arthur Meyer's 

 experiments on the effect of light and darkness in producing the layers of 

 starch grains with different results. Starch grains may be permanently 

 coloured by staining with a drop of alcoholic iodine solution and mounting 

 in Canada balsam. A short criticism of assimilation, of Haberlandt and 

 Nemec's gravitation theory as regards the starch sheath, of an enzyme 

 as being the possible inulin-forming body, and of the absence of wound 

 cork in certain tubers concludes the paper. — G. F. S.-E. 



Stomata. 



Stomata, Mechanism Of. By Edwin Bingham Copeland, Stam- 

 ford University, California {Ann. Bot. xvi. No. lxii. pp. 327-364, pi. 13). 

 — For the last hundred years, perhaps, the student of botany has found 

 a special point of interest in stomata, and yet, as shown by this paper, 

 there still remains an extensive field for observation. " From all points 

 of view, anatomical and physiological, the stomata have received more 

 constant and lasting attention probably than any other single vegetative 

 structure in the plant, and yet recent literature on the subject is most 

 contradictory, not only as to the mechanism of their movements, but 

 even as to the conditions which influence their opening and closing." 

 The relation between the structure of stomata and their movements 

 forms the theme proper of this interesting paper. " But as this takes for 

 granted the occurrence of movement under certain conditions, we must 

 first determine what these conditions are, and how, aside from the struc- 

 ture of the stomata, the conditions are met." Having thus shown the 



