ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 609 



Bracts of Cruciferse.* — M. Beauvisage points out that the absence of 

 bracts from the inflorescence of Cruciferse is not nearly so constant a 

 character as is usually stated in text-books. In the wall-flower a tri- 

 angular elevated patch at the base of each pedicel represents the entirely 

 adnate bract. 



Physiological Anatomy of Stipules.f — Herr 0. Schultz classifies 

 stipules, from a physiological point of view, under three heads : — 

 (1) those which serve for protection ; (2) those which serve for nutrition, 

 there being also transitional forms between these two ; and (3) those 

 which have become abortive and functionless. To these may be added 

 those which are transformed into bud-scales, and those which are 

 transformed into ochreae. 



Those stipules which serve for nutriment or assimilation make their 

 appearance at the same time as the leaves, and endure as long ; protec- 

 tion against freezing is often afforded by the presence of anthocyan in 

 the cells, giving them a red colour. The anatomy of stipules of this 

 kind agrees in almost all respects with that of the leaves themselves. 



Stipules which serve for protection may again be divided into those 

 with and those without mechanical strengthenings. The palisade-tissue 

 of ordinary leaves is in them altogether wanting ; stomata are absent or 

 very few in number ; other trichomic structures are usually wanting ; 

 anthocyan is very frequently present in the cells. Where there is 

 mechanical strengthening, it is of various kinds : — great thickening and 

 cuticularization of the cell- walls, sclerenchymatous hardening, formation 

 of periderm, &c. 



When stipules are converted into bud-scales, they are usually 

 abundantly furnished with trichomes, bristles, woolly hairs, or colleters, 

 which serve to reduce transpiration ; the tissue itself may also be 

 modified in various ways, as in protecting stij)ules. Examples of stipules 

 transformed into ochrese are furnished by the Platanacete and Poly- 

 gonacese. Structurally they may belong to the class of protecting 

 stipules either with or without mechanical strengthening. 



Foliar Sheath of the Salicornieae.l — M. P. A. Dangeard points out 

 that it is well known that in Salicornia the foliar bundles, when tra- 

 versing the cortex more or less obliquely, give out descending branches, 

 which ramify and anastomose in a rosette in the interior of the cortical 

 parenchyma. The author has studied various types in this family, and 

 gives the following as his conclusions : — That in the Salicorniege {Arthro- 

 cnemum, Salicornia, JSalostachys, Halocnemum) there is a foliar sheath 

 with palisade-tissue. This sheath is altogether distinct from the cortex 

 in the internodes {Arihrocnemum fruticosum), but is sometimes confounded 

 with the cortex in the lower part of the internodes ; it incloses a large 

 number of fibrovascular bundles, which proceed from two lateral and 

 symmetrical foliar bundles. The large spiral cells which are met with 

 in Salicornia peruviana, S. virginica, Arthrocnemum fruticosum, and A. ? 

 amhiguum, belong to this foliar sheath. The formation of such a sheath 

 ought to be attributed to a decurrence of the edges of the limb, a point 

 which may be easily seen in Kalidium foliatum, which has the leaves 

 alternate. 



* Bull. Soc. Bot. Lyon, 1887. See Morot's Journ. Bot., ii. (1883), Eev. Bibl., 

 p. 1. t Flora, Ixxi. (1888) pp. 97-107, 113-128 (1 pi.). 



X Bull. Soc. Bot. France, xxxv. (1888) pp. 157-60. 



