1905] LYON—THE SPORE COATS OF SELAGINELLA 293 
former paper‘ when I interpreted the inner region of the exospore as 
a separate membrane ? 
In a late paper by BEER,‘ the author states that he has observed 
a separation of coats in the pollen grains of certain Onagraceae that 
is quite comparable to the condition described by FITTING as occur- 
ting normally in the megaspores of certain species of Selaginella. 
His forthcoming paper on the subject will be one of interest, especially 
if he finds evidence to support Frrrinc’s view of protoplasm acting 
at a distance. 
THe UNIVERSITY oF CHICAGO. 
EXPLANATION OF PLATES X AND XI. 
In all figures, @ indicates mother cell membrane; 5 the protoplast, c the spore 
membrane, d the nucleolus, the nucleus, and v the vacuole. 
PLATE X. Selaginella rupestris. 
Fic. 1. Median section of megaspore mother cell with three sporogenous 
cells that fail to form spores. X 1250. 
Fic. 2. Not quite median section of megaspore mother cell showing slight 
lobing, before division into two spores. 1250. 
Fic. 3. Nearly median section of two megaspores not completely separated 
from each other; that portion of the spore membrane between the two proto- 
Plasts 1S apparently formed by the lobing of the mother cell and not in connection 
with a nuclear plate. X1250. 
Fic. 4. Median section of megaspore after the formation of a large central 
vacuole and at the time the spore membrane shows a region differentiating into 
““ £xospore or outside coat; e, region differentiating into exospore; /, possibly 
currents of solution passing into spore from sporangium. X 600. 
5. Sections of two megaspores lying near the sporangium wall; by 
Greater growth of the spore membrane at one side the protoplast has come to lie 
near the apex of the spore; the spore A is in nearly median section, B is not; ¢, 
“spore, S, sporogenous cells that failed to divide into megaspores. X6c0. 
ke Portion of median section of megaspore (drawing not completed at 
these dig show further differentiation of spore membrane; ¢, exospore showing 
erent regions. X6oo. 
ooo 7. Apical portion of median section of more advanced stage of mega- 
dias Show the first appearance of the second coat—endospore—and the 
8S in the exospore; the undifferentiated part of the spore membrane (h) 
a as FLoRENcE, A study of the sporangia and gametophytes of Selaginella 
- Claginella rupestris. Bor. GAZETTE 31:124-193- pls. 5-9- 190T- 
3: EER, RUDOLPH, The present position of cell-wall research. New Phytologist 
“1590-164, 1904. ; 
Fig, 
