128 BOTANICAL GAZETTE [repre 
that so long a period is not needed, since many plants which he 
reached the spore mother cell stage in the autumn resume ther 
development when brought into the laboratory early in the winte 
Again, my observations hardly allow the supposition that the sporang: 
merely continue their development until checked by cold weathit. 
Of course every botanist has noticed dandelions blossoming in Decta- 
ber and January, and fruit trees bearing a second set of flowers in 
autuinn. The change in the habits of north temperate plants wht 
taken to a warmer climate is also well known, but they doubtlesssil 
have their resting periods. I should be inclined to think that th | 
stage at which a sporangium rests for the winter is determined largeh 
by its power to withstand unfavorable conditions. It has been noticl 
that the later the material is collected the more promptly it result 
its development. This suggests that the resting period is not one t 
absolute inactivity— CHARLES CHAMBERLAIN, Zhe University of Chicas 
EXPLANATION OF PLATE XI. s 
All figures are drawn with a Bausch and Lomb camera lucida, ¢ 
ocular no. 2 and Zeiss apochromatic 2™", homogeneous immersion obj 
The figures have been reduced by photography to one-half the size of 
original drawings. 
1G. I. Sporangium of Osmunda cinnamomea L. collected Novem 
1897. . 
FIG. 2. Microsporangium of Pinus Laricio Poir. collected 0 
Fic. 3. The same, collected January 3, 1898. 
Fic, 4. The same, collected April 4, 1896. 4 
Fig, 5, Microsporangium of C upressus Lawsoniana Murr., coll cted 
ber 1, 1897. 
IG. 6. Microsporangium of Zaxus baccata, Canadense Willd. co 
October 1, 1897. 
he 7: Microsporangium of Populus monilifera Ait. collected | 
25; 1896. ’ a 
\ Fie. 8. Micros 
7s 1897, 
; Fig, 9, Microsporangium of 4/nus glutinosa Willd. collected Apt 
1097. 
porangia of Corylus Americana Walt. collected Dé 
