ON THE FORMS OF POLLEN-GRAINS. 283 
botanists as a mere variety of the former. Indeed, Z. major has been 
described, on high authority, as only a “larger development in all its 
parts, from its moister habitat," of L. corniculatus. 
Now, however, I am to show that the pollen-grains of Lotus major 
are uniformly smaller than those of L. corniculatus. In my note-book 
many measurements, made in several different months and years, are 
entered of the pollen-grains of these plants; and although the absolute 
size of these grains in one or other of the two plants often appears to 
have differed slightly, the relative size has always been plainly distinct. 
In every case the larger size of the pollen-grains of Lotus corniéulatus 
was obvious. Hente I have frequently repeated the measurements 
during this summer ; and, as the results are still uniform, this notice is 
drawn up, with a woodcut, for the ‘ Journal of Botany. 
In the following woodcut, of the mere outlines, all the objects are 
done to the same scale of ;,);5ths of an English inch; and the mea- 
surements are given in vulgar fractions of that inch. 
ZQ oP 
Fig. 1. The pollen-grain of Ranunculus arvensis, large and rough on 
the surface. Diameter 43, of an inch. 
Fig. 2. The pollen-grains of Ranunculus hirsutus, much smaller and 
smoother than the preceding. Diameter about 41; of an inch, 
Fig. 3. Pollen-grains of Lotus corniculatus; long diameter i75; 
short diameter qy} of an inch. 
ig. 4. Pollen-grains of Lotus major; long diameter zq'5q> short 
diameter 441. of an inch. 
While noticing that this is only a difference of size between the pollen- 
grains of Lotus corniculatus and L. major, it may be granted that this 
fact, from its constancy, must have some significance; and it is really 
here the most certain single difference between these two plants. 
just so is the difference of size between the tissue-cells of Hymenophyl- 
