ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 83 



tropical. The author has made a special study of E. nevadensis, com- 

 paring it with several of the other species. 



The stem bears no leaves, but at the nodes of the young shoots are 

 two or three scale-like bracts one to six lines long. These scales are in 

 all probability rudimentary leaves, yet they do no leaf work, having 

 no fibrovascular connection with the stem. The epiderm of the stem is 

 rather tough, and is composed of irregularly shaped cells. The cortex 

 is for the most part made up of palisade-parenchyme, containing chloro- 

 phyll. Scattered singly or in groups of from two to ten within the 

 cortex, and also in the pith, are found very long sclerenchymatous fibres. 

 They are thick-walled and shining. Next within the cortex is found the 

 bundle-sheath of very thin-walled cells, and vrithin this the phloem. 

 The xylem-area resembles that of Pinus, having rectangular-shaped 

 cells with heavy lignified walls. The medullary rays are not very 

 prominent, and the pith consists of large irregular cells. 



Anatomy of the Wood of Laurinese.* — Herr E. Knoblauch has 

 examined the wood of a large number of species of Laurinese, in order to 

 determine whether characters can be obtained from it for the determina- 

 tion of the genus or the order. As far as generic characters are con- 

 cerned, the results were negative, and for the order no single character 

 can be relied on, but only the concurrence of a number of characters, 

 each of which may belong also to other natural orders. These are as 

 follows : — Vessels in the annual rings of about uniform width (only in 

 Sassafras are they very broad in the S]3ring, very narrow in the autumn 

 wood) ; in some species they are broader in the autumn-wood, quite 

 visible to the naked eye, usually solitary; and in regular radial rows, 

 less often in irregular groups. The transverse walls usually perforated 

 by roundish or elliptical orifices, sometimes also scalariform, rarely the 

 latter only. In the walls which separate them from one another the 

 vessels have close roundish clearly bordered pits, and in those which 

 separate them from the wood-parenchyme and the medullary rays nume- 

 rous large pits of variable form, usually round or elliptical and slightly 

 or evidently bordered, often passing into one another. The wood- 

 parenchyme-cells are always present, but vary in number and arrange- 

 ment and in the thickness of their walls. The medullary rays are of 

 one kind only, the cells usually in from one to five rows ; those in the 

 centre and at the angles high and short. The rays are very close 

 together, so that in the breadth of the medullary rays there are usually 

 from 1 to 20 wood-parenchyme-cells and from 1 to 3 vessels. In many 

 species a larger or smaller number of the wood-parenchyme-cells and 

 those of the medullary rays are transformed into large thin-walled oil- 

 cells without pits. 



Radial Connection of the Vessels and Wood-parenchyme.f — Herr 

 F. Gnentzsch states that radial connections are much more common 

 than is usually supposed between the vessels and the wood-parenchyme 

 of successive annual rings in dicotyledonous trees. The observations 

 were made on a large number of trees and shrubs belonging to many 

 different natural orders. The annual rings are not by any means always 

 completely isolated : the xylem-vessels at the boundary line of two suc- 

 cessive rings are, in fact, usually in connection with one another, either 

 directly, or by tracheides, which must then be considered as equivalent 



* Flora, Ixxi. (1888) pp. 339-400 (1 pi). f Ibid., pp. 309-35 (1 pL). 



G 2 



