ZOOLOGY AND BOTANY, MIOROSOOPY, ETC. 609 



Relation of Secretory Channels to Laticiferous Vessels. * — M. A. 

 Trecul states that as the couteuts of secretory channels and laticiferous 

 vessels are analogous in physical and physiological properties, ho proposes 

 to employ the name laticiferous vessels for both sets of organs. Secretory 

 channels may occur in the root, stem, or leaves. In Argemone, Podostemon, 

 Lactiica, &c., they may be seen forming a network near the surface of the 

 root, while in Angelica syloestris, Opoponax Chironium, &c., the channels 

 form a system extending through the whole plant. 



The author calls attention to the simultaneous existence in tlie Compo- 

 sitfB of secretory channels and laticiferous vessels. In the Ciclioriaces9 

 laticiferous vessels with a membranous envelope exist, while in the 

 Senecionideae and Asteroidese tbe oleo-resinous channels have no envelope. 

 In laticiferous vessels the latex is generally in a state of emulsion ; rarely 

 the juice is limpid. In the secretory channels, on the contrary, the 

 emulsified condition is rarely found. 



The latex of certain plants is decidedly nutritive, and in 1862 the 

 author gave examples of certain Umbelliferse, where the oleo-resinous juico 

 l^roduces true cellules in the interior of the channels. This may also be 

 seen in the branches of Brucea ferruginea. 



Laticiferous vessels of Calophylluni.t — M. A. Trecul states that in 1865 

 he described the structure of the leaves of Calophyllum Calaha, and pointed 

 out the relation of the channels containing white milky latex to the fibro- 

 vascular system. On the edge of the leaf, in the group of thickened cells 

 forming the edge, there is a channel full of latex running at the side of the 

 marginal vein. 



M. J. Vesque has confirmed the observations published by the author in 

 1865. Spiral vessels were observed attached to the surface of the secretory 

 or laticiferous channels interposed to the secondary veins, in the middle of 

 the parenchyma which separates these parallel veins. These tracheids 

 extend along the side of the channels in the form of bundles, and in trans- 

 verse section are arc-shaped, and in from one to four layers. 



These secretory channels are then surrounded in a great measure by 

 the tracheids ; but this is not all, as the tracheids, which are intimately 

 connected with the surface of the secretory channels, communicate with 

 the secondary veins, by bundles composed of narrow tracheids, and some 

 fibres, in the same manner as those which are in contact \^ith the secretory 

 channels. The reservoirs of water are only the spiral cells themselves. 



The author concludes that it is the latex which furnishes nutritive 

 elements to the transverse bundles, and to those communicating with the 

 secondary veins. 



Anatomical peculiarities of Echites peltata.J — M. L. de Saldanha has 

 made a study of the stem and leaves of Echites peltata Veil. The stem is 

 only a few millimetres in thickness, and contains an extremely astringent 

 juice ; its richness in tannin is remarkable. A transverse section of the 

 stem shows the disproportion that exists between the diameter of tracheids, 

 and of certain vessels that are found exterior to the woody cylinder. The 

 diameter of the tracheids is extremely email, while that of the vessels in 

 the periphery is large. The stem also contains laticiferous vessels, the latex 

 being of a yellowish or golden-yellow colour. 



Meristem of the Medullary rays of Cytisus Laburnum.§ — From an 

 examination of the medullary rays of the laburnum, showing that some of 



* Comptes Rondus, civ. (1887) pp. 1034-9. f Ibid., pp 27-32 



I CR. Soc. R. Bot. BcIr., 1887, pp. G2-3. 



§ Ber. Deutsch. Bot. Gesdl., iv. (1886) pp. 144-50 (1 pi.). 



