9 G SUMMARY OF CURRENT RESEARCHES RELATING TO 
Leaves and Scales of Lathrsea.* * * § — From experiments on the leaves 
of Lathraea and allied saprophytic genera ( Pedicularis , Bhinanthus , 
Odontites ), Mr. P. Groom finds a very large excretion of water through 
the dome-shaped glands, the cuticle of which is perforated by a pore ; 
thus agreeing with the view of Goebel rather than with that of Haber- 
landt. There is a close connection between these glands and the 
tracheids in the fine vascular bundles. The leaves of Lathraea squa- 
maria excrete a certain amount of chalk ; their fleshy mesophyll con- 
tains a great quantity of large starch-grains. The pocket-like leaves of 
Lathraea are therefore both excretory organs and reservoirs for carbo- 
hydrates. 
Phenomena of Torsion.! — From a series of experiments made chiefly 
on the bamboo, Herr W. Dingier draws the following conclusions. The 
process of twisting falls under the general problem of a cylindrical 
system which ultimately becomes conical, constructed of material points 
arranged in a spiral. The general mechanical processes of such a 
system, and their geometrical conditions, are discussed at length. The 
vigour of growth of the various sections of the internodal zone of the 
lower portion of a twisted stem corresponds to the vigour of growth of 
corresponding successive internodes of normal vigorous stems, if it is 
assumed that the inappreciable resistances in the twisted stem decrease 
in arithmetical progression from below upwards. 
Causes of Anisophylly.J — The cause of anisophylly in leaves must, 
according to Herr W. Figdor, be sought in the influence of light. In 
the course of the later development of a shoot, the unequal growth of 
the leaves becomes gradually obliterated, and may finally, under the 
influence of light, become reversed, so that the originally small leaves 
on the morphologically upper side of the axis become large leaves, and 
vice versa. 
Peduncle of Cycadese.§ — According to Dr. D. H. Scott, the pe- 
duncle of certain Cycads belonging to the genera Stangeria, Boivenia , 
Zamia, and Ceratozamia , have mesarch vascular bundles comparable to 
those of the leaves, to which they have hitherto been supposed to be 
confined. He regards this as confirming the theory of the descent of 
the Cycadeae from the Filicineae rather than from the Lycopodineae. 
The Cycadean type of vascular bundles, one of the most ancient of 
anatomical characters, was not originally a mere peculiarity of the leaf, 
but rather represents the vestige of a primitive organisation which was 
once common to the stem also. In recent Cycads the stem has all but 
lost this character ; it appears to have survived only in certain pe- 
duncles. 
Structure of American Conifers. || — Mr. H. Trimble and the late 
Prof. E. S. Bastin give a description of a number of the more important 
American Conifers, and of the characters by which they may be dis- 
* Ann. of Bot., xi. (1897) pp. 385-98 (1 fig.). Cf. this Journal, 1897, p. 406. 
t Flora, lxxxiv. (1897) Erganzbd., pp. 249-342 (3 pis.). 
t Be*. Deutsch. Bot. Gesell., xv. (1897) Gen.-vers.-Heft, pp. 70-9. 
§ Ann. of Bot., xi. (1897) pp. 399-419 (2 pis.). 
|| ‘Some North American Coniferae,’ Philadelphia, 1897, 124 pp.,2 pis. and 
