256 
ORIGINAL ARTICLES. 
rays bear no relation to these rays.— C. torulosa. Sanio, C. Ver- 
gleichende untersuchungen iiber den Bau und die Entwickelnng 
des Korkes. Pringsheim’s Jahrb. ii.103, tab. xiii. On the structure 
and development of the cortical layers. # —Bindley, J. Veg. King¬ 
dom, 250.—Henfrey, A. Microg. Diet. ‘Wood.’ 
Cycadeae. Moldenhauer, J. P. Beitrage z. Anatomie der Pflanzen, 
1812, 111. —Treviranus. Vom inwendigenBau der Grewachse, 1806, 
130.—Link. Elementa Phil. Bot 73.—Brongniart, A. Becherches 
sur lOrganisation des tiges des Cycadees. Ann. Sc. Wat. 1829, 
xvi. 398, with 2 plates. An account of the Anatomy of Cycas 
revoluta. The stem presents a central parenchymatous pith, two 
concentric fibrous zones, separated by a narrow layer of paren¬ 
chyma, and a thick cortical parenchyma, traversed by vascular 
bundles passing to the leaves. The fibrous zones are composed 
solely of greatly elongated, tapering, dotted cells. Dotted and 
spiral vessels are not found in the stem. Grum-canals occur in 
both the medullary and cortical parenchyma.— Cycas and Zamia. 
Buckland, W. On the Cycadeoideae. G-eol. Trans. Ser. ii. ii. 46.— 
H. v. Mohl. Ueber den Bau des Cycadeen-Stammes und sein 
Yerhaltniss zu dem Stamme der Coniferen und Baum-farn. 
Miinchen Dkschrift. K. b. Ac. Wiss. x. (1832) Ext. pp. 46, with 
3 pi. M. Mohl’s observations upon Cycas latifolia and C. revoluta 
confirm the general analogy between the wood of Cycads and 
Conifers maintained by Brongniart; he points out, however, the 
inaccuracy of his statement that Cycadeae are destitute of 
vessels, that they possess the concentric wood-zones, of which 
the inner stands in no relation to the leaves, and that they are 
without liber. Pith occupies the greater portion of the stem. 
The wood consists of two immediately superimposed layers of 
nearly equal thickness, of which the inner is the wood-mass, the 
outer liber. The inner woody zone is closed and traversed by 
medullary rays ; it consists of porous cells, which are regarded 
as belonging to the vascular system, because the author finds the 
spiral vessels gradually pass into slit-marked, and these into the 
dotted tubes which compose the wood of Cycadeae, without 
admixture of prosenchyma. The liber ring consists of short, 
truncate, superimposed cells. The parenchyma of the pith and 
bark is traversed by branching intercellular canals, filled with a 
colourless gum. The course of the vascular bundles is described 
in detail, and a comparison of Cycadeous structure with that of 
Palms and Tree-ferns (between which, in respect of anatomical 
relations, they are held to be intermediate), is entered into.— 
Corda. Deb. d. Bau des Pflanzenstammes, in Weitenweber’s Bei¬ 
trage z. JSTatur- und Heilwiss. Prag. 1836, i. Hft. 23— Zamia. 
Link. H. E. leones Anat. Bot. 1837, fasc, ii. xv. 1, 3.—Meyen, 
* In this paper the development of cork-tissue in the cortical layers of numerous 
species is described and illustrated by figures. I have not separately referred to 
them. 
