4 
1899 | MICROSPORANGIA OF HEMEROCALLIS FULVA 87 
primitive condition. Since extra tube nuclei are produced only 
by fragmentation, so far as known, such division may representa 
pathological condition. It is possible that direct division in the 
higher plants never represents anything more. 
SUMMARY. 
1. Three or four hypodermal cells of each sporangium 
become differentiated as the archesporial cells. The wall of a 
sporangium consists of three layers exclusive of the epidermis. 
The tapetum is a physiological rather than a morphological 
structure, the peripheral part being organized from the wall 
layers and the axial part from the general tissue. 
2. The spindle appears bipolar from its first appearance, 
being dome-shaped in the early stages. No trace of multipolar 
spindles was observed. The spindles often persist for a consid- 
erable time after division is complete. Bodies having the 
appearance of centrosomes are frequently seen at the poles. 
3. The Origin of the supernumerary microspores was not 
absolutely ‘determined. In many cases where their origin was 
indicated by spindles or otherwise they appeared to arise by the 
indirect division of one of the tetrad nuclei. 
* The tube nucleus frequently divides by direct division, 
forming sometimes as many as Six or eight nuclei. 
: In conclusion I wish to express my thanks to Dr. W. A. 
Kellerman and Mr. J. H. Schaffner for valuable assistance and 
criticism, 
Co_umsus, O. 
EXPLANATION OF PLATES VII AND VIII. 
ae psi seh drawn with a camera lucida and are reduced to three 
objective an i mena size. Fig.32 was drawn with a Bausch and Lomb ?2 
22, 23 with a ea He. 2 ocular (X 1200); figs. 3) 4s 91 10, TF. 15s 24% 
with a Ba €itz |, objective and a Leitz no. 4 ocular (< 1600); all others 
usch and Lomb ,, objective and a Zeiss no. 6 ocular (X 1600). 
FIG. 1. Micros . ee ae Ps d 
pore mother-cell in very early stage of first division, show 
ing dark b. : 
to the cel] oo nucleus and cytoplasmic radiations extending outward 
