No. 387.] PLANT MORPHOLOGY AND PHYSIOLOGY. ` 203 
The cleistogamic flowers of both sorts produce more seeds than 
the conspicuous ones. 
R. E. B. McKenney: Observations on some Monocotyledonous 
LEmbryo-sacs. — The development of two species of Scilla, S. Ayacin- 
thoides and S. campanulata, was described and reference made to the 
development of other Monocotyledonous Embryo-sacs. The arche- 
sporial cell is formed from a sub-epidermal cell. This cell grows 
rapidly and a small cell is cut off by a periclinal wall — the primary 
tapetal cell. The primary tapetal cell divides later by a periclinal 
wall, thus giving rise to an inner and an outer tapetal cell. The 
archesporial cell continues to grow and divides twice, giving rise to 
three cells. The upper one of these cells remains uni-nucleate, the 
lower becomes tetra-nucleate, and the middle one develops into the 
embryo-sac with its eight nuclei. It seems probable that each of 
the eight nuclei of the embryo-sac, as well as the four in the cell 
below, represents a macrospore. Hence, the embryo-sac may be 
considered as two sporocytes which never develop the separating 
wall. On this hypothesis, the cell above the embryo-sac and also the 
one below, each represents a sporocyte. Two cases in which such a 
partition in the embryo-sac has been observed were mentioned, one 
by Mann in Myosurus, and one by the writer in Lilium candidum. 
Especial attention was called to the extra-nuclear origin of the spindle 
fibres and to the entire absence of centrosomes. The author has’ 
slides made from Lilium tigrinum and L. candidum, which exactly 
confirm Mottier’s statements as to the origin of the spindle in 
Lilium. 
R. E. B. McKenney: The Structure and Function of Crystal Cells 
in Sensitive Plants.—The crystal cells in sensitive plants form a 
complete sheath around the bundle cylinder in stems and a half 
sheath around the bast of the leaf bundles. Each cell contains a 
single large crystal. These crystals usually have the shape of a 
hexagonal prism. Each one is imbedded in apparently homogeneous 
cytoplasm. The nucleus is very small and homogeneous, but a 
nucleolus is wanting. Sap vacuoles and starch are also absent. 
From tests made with hydrochloric acid, nitric acid, caustic potash, 
fluoric acid, etc., it seems probable that these crystals are very insoluble 
silicates. They are found in the ash after burning the plants. . These 
silicate crystals are entirely wanting in the cotyledons and only make 
their appearance in the first leaf after it has been expanded for a day 
or two. ‘The crystals are first found in the cells of the sheath at the 
