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204 ._ THE AMERICAN NATURALIST.  [VOL. XXXIII. 
distal ends of the main bundles of the leaf as small spicular bodies. 
These gradually grow and assume the adult shape, but as they grow 
the nucleus’ becomes gradually smaller until it reaches its minimum 
size. Beginning with the cells at the distal end of the bundles, the 
crystals are developed in basipital fashion along the entire course of 
the bundle. The same course of development takes place in the bud 
leaves of old plants, only the crystals are fully formed before the-leaf 
expands. These crystals were observed in several species of Mimosa, 
Acacia, and Oxalis. From the researches of Dutrochet and others it 
seemed as though the phloem was the region for the transmission of 
stimuli. However, since the crystal cells are closely applied against 
the phloem, and since they are best developed in the most sensitive 
plants and most poorly in least sensitive plants, it seems more proba- 
ble that these cells constitute the maz lines of transmission of 
stimuli. This tissue leads straight down to the pulvinus, but there 
are no crystals in the latter. 
AMELIA C. SMITH: Structure and Parasitism of Aphylion uni- 
Jorum. — The most conspicuous features of this plant are its para- 
sitism on Aster corymbosus and the degradation attendant upon its 
parasitic habit as expressed by: (1) Absence of chlorophyll; degen- 
eration of true leaves; loss of root hairs, and probably of root cap ; 
reduction and degeneration of the bundle system, and relatively 
greater development of the phloem than of the xylem ; small size of 
seed, and primitive embryo developed within a mass of tissue which 
is probably precocious endosperm. (2) Infrequence of stomata. 
Where present they are on the more exposed places, z.e., outer sur- 
face of upper bract-leaves, upper part of flower stalks, and outer 
surface of calyx and corolla. (3) Abundance of starch. Starch is 
present in great quantities in root, stems, leaves, and carpellary 
tissue. 
Sieve tubes seem to be entirely absent from the stem. The embryo 
is simply a mass of undifferentiated cells, ż.e., it is not distinguish- 
able into cotyledons, plumule, and radicle. The use of the starch is 
problematic. The quantity stored in the endosperm is infinitesimal 
compared with that stored in other parts of the plant. 
Dr. M. A. Howe: On the Occurrence of Tubers in the Hepatice. 
— The existence in this group of plants of tubers serving for vegeta- 
tion propagation seems to have been, until very recently, almost 
unknown to plant morphologists. There are, however, four or five 
species, mostly of the genus Anthoceros, in which the occurrence of 
