292 
Anatomie. 
layers and b) rootlets free from a fungus with root-cap, root-hairs, 
definite hypoderma and a cortex of some 20 layers. 
The roots of twenty two species of the Meliaceae were examined 
and an endotrophic mycorhiza was found to be present in more 
than half the number. The mycorhiza seems to become disintegra- 
ted in deeper cells of the cortex. In Cedrela Toona, C. febrifuga and 
Swietenia mahagoni the hypodermal cells bear an endodermis-like 
band of thickening on the radial walls. Other structural details are 
also mentioned. D. T. Gwynne-Vaughan. 
Hill, A. W., The seedlings of certain Pseudo-monocy tole- 
dons. (Rept. Brit. Assoc. York (1906). p. 763. 1907.) 
Certain bulbous and rhizomatous species of Peperomia possess 
two cotyledons both of which are at first absorbing Organs. Later 
on one only is withdrawn and expanded in the air; the other never 
emerges and the seedlings are apparently monocotyledonous. These 
cases suggest a line of evolution for such normal monocotyledonous 
Orders as the Araceae, etc. For it is possible that the absorbent 
cotyledon and the so-called “first leaf” may stand in the same relation 
to each other as the two cotyledons of the Peperomias. The mono¬ 
cotyledonous habit of germination may have originated in the as- 
sumption of different functions by the two cotyledons. 
The genus Cyclamen is also apparently monocotyledonous. But 
the rudiment of a second cotyledon is always present and visible 
and may develope into a normal green leaf if the first cotyledon 
should suffer damage. D. T. Gwynne-Vaughan. 
Hill, T. G., On the seedling structure of certain Centrospermae. 
(Rept. Brit. Assoc. York (1906). p. 760—761. 1907.) 
The seedlings of several plants belonging to the Orders Aizoaceae, 
Caryophyllaceae, Portulacaceae, and Chenopodiaceae were investigated 
and in all the transition phenomena were found to be essentially of 
the same nature as those shewn in Amaranthus hypochondriacus 
which are described as follows: Each cotyledon has a single bündle. 
Bifurcation of the bündle and rotation of the xylem, towards the 
exarch position it occupies in the root, commences some wayup the 
petiole. The rotation is completed in the cotyledonary node and the 
divided phloems of the two cotyledonary traces fuse across to form 
the diarch stele of the root. In Allionia albida and Mirabilis diva- 
ricata (.Nyctaginaceae ) the transition is somewhat different. Two col- 
lateral bundles and a small median Strand of xylem enter the axis 
from each cotyledon and together with the plumular traces give 
rise to a tetrarch formation in the upper part of the hypocotyl. 
Lower down, however, the xylem Strands in the plane of the coty¬ 
ledons alone persist, while the four phloem Strands fuse to two so 
that here also a diarch stele is eventually produced. 
D. T. Gwynne-Vaughan. 
Imperatori, L., Contribuzione allo Studio anatomico e fun- 
zionale dei Nettarii fiorali. (8°. 87 pp. avec 37 figures. Ma- 
cerata, 1906.) 
Apres avoir donne un apergu general de l’historique des con- 
naissances actuelles sur les nectaires au point de vue de leur na¬ 
ture, structure et fonction, l’auteur montre quel a ete le Programme 
