442 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
emergences, from which a fluid is excreted. Fagrsea littoralis has a 
number of light-coloured spots on the leaf, consisting of a solid small- 
celled tissue, which excretes a sweet fluid through a pore. Vaccinium 
Teysmanni has extra-floral nectaries at the point of junction of the petiole 
with the lamina. In Shorea stenoptera there are on both sides of the 
leaves spots which exude nectar. 
Leaf and Stem.* — Herr H. Potonie traces back all the organs of the 
higher plants to a single morphological fundamental organ, a forking 
thallose structure. The leaves of the higher plants have, in the course 
of generations, sprung from portions of a thallus, the forked branch being 
outgrown, and the lateral branches becoming leaves. 
Assimilating Organs of the Asparagege.f — Herr J. Reinke describes 
in detail the structure of the assimilating organs in the various genera 
of the Asparageas — Asparagus , Buscus , Danae , Semele — in all of which 
the leaves are either greatly reduced, or are replaced by cladodes. The 
form of the leaves on seedling plants of Semele androgyna and Danae 
racemosa renders it probable that these genera and Buscus are most 
nearly allied to Cordyline among Liliacese, while Asparagus is more 
probably descended from the Convallariese. Whether the development 
of cladodes in the Asparageae rendered the leaves superfluous, or whether 
they made their appearance to compensate the reduction in the leaf- 
surface, we have no evidence. 
Floating Leaves.* — Herr E. Wollenweber notes the following pe- 
culiarities of floating leaves. The margin is almost always entire. 
The growth of the petiole or of the leaf-bearing stem is regulated by the 
depth of the water. The epiderm has a thick cuticle, furnished with a 
coating of wax. The assimilating tissue always consists of a well- 
developed palisade-parenchyme ; there is no spongy parenchyme, the 
system of air-chambers being located in the lower part of the lamina. 
W ith very few exceptions, stomates are wanting on submerged leaves *, 
in floating leaves they occur almost exclusively on the upper surface. 
The stomates are very rarely depressed ; the pore forms a kind of 
funnel to the air-cavity, a contrivance probably for preventing the 
capillary stoppage of the stomate by water. The author classifies float- 
ing plants under various groups, according as submerged leaves or aerial 
leaves are occasionally developed in addition to the floating leaves. 
Lodicules of Grasses.§ — Dr. W. W. Rowlee argues that the lodicules 
of grasses correspond to a reduced perianth. The three lodicules in the 
flower of Arundinaria alternate on the axis with the stamens, and may 
therefore be considered the inner whorl or petals. The stamens are 
directly opposite the midribs of the carpels, and indicate that the inner 
whorl of stamens, present in some bamboos, is suppressed in Arundi- 
naria. 
Chimney-shaped Stomates. || — On Holacantha Emory i, a prickly leaf- 
less shrub, native of the arid regions of Southern Arizona, Prof. C. E. 
* SB. Gesell. Naturf. Freunde Berlin, 1897, pp. 183-91. 
t Jalirb. f. wiss. Bot. (Pfeifer u. Strasburger), xxxi. (1898) pp. 207-72 (26 figs.). 
t Yergleich. Anat. d. Scliwimmblatter, Bonn, 1897, 319 pp. See Bot. Centralbl., 
Ixxiv. (1898) p. 184. § Bot. Gazette, xxv. (1898) pp. 199-203 (2 figs.). 
|| Rep. Brit. Ass. Toronto, 1897 (1898) p. 861. 
