THE DEVELOPMENT OF THE MICROSPORANGIUM 
AND MICROSPORES IN CONVALLARIA AND 
POTAMOGETON. 
KARL M. WIEGAND. 
(WITH PLATES XXIV—XXv) 
Durinc the past decade perhaps no one portion of the field 
of botany has been worked upon so much as that which deals 
directly with the organs concerned in the sexual process. Espe- 
cially is this true of the higher plants, but a careful survey of 
the present condition of our knowledge on this very point shows 
that some of the most vital questions have as yet received no 
solution. The researches of such men as Hofmeister, Stras- 
burger, Guignard, and Warming have discovered facts in regard 
to the ovule, the embryo-sac, and the cell which have already 
become so universally known as to need no further mention here. 
But we still know almost nothing about the essential significance 
of some phenomena of most common occurrence, and ary 
questions have as yet been investigated only in connection with 
so few plants that generalizations are extremely unsafe, It — 
principally with the hope of increasing, if only by a few species, 
the range of observations that the present studies were under- 
taken. 
The choice of subjects signifies very little. 
much more by the necessity of using plants obtaina 
times rather than by an idea that they all represente 
types of structure. 
It was influenced 
ble at certain 
d different 
METHODS. ‘al 
The methods employed in this work differ in no gies 
way from those so often described in recent cy tological i 
consequently it is scarcely necessary to repeat them pate 
detail. The following general statements are intended ape 
for those who wish simply to know the stains, fixing @ 
chosen for the work. 
gents, 
: [NOVEMBER 
328 
