2h peaeskiag 
THE MICRUSCOPE. AY 
CONVOLVULUS SOLDANELLA, L. 
(Calystegia Soldenella, R. Br.) 
Worthington G. Smith, F. L. S., delineates the pollen of this 
species as shown in Fig. 14. I have not seen it. 
CONVOLVYULUS SPITHAMAUS, L. 
(Calystegia Spithamea, Persh.) 
Here the grains are again subspherical, about 34, inch in dia- 
meter, and the entire surface is clothed with a minute hispid growth 
ga's7 inch in length. 
CONVOLYULUS SEPIUM, L. 
(Calystegia Sepium, R. Br.) 
Again the grains are simply spherical, about 54; inch in diam- 
eter; the surface, however, is entirely clothed with minute villi 
measuring ;-'z5 inch in length. There appear to be no markings or 
sulci, and no appendages of any kind, except the fine hirsute growth 
from the extine. The pollen may perhaps be distinguished from 
that of Colvolvulus spithamceus by the rather larger size of the 
grains. Otherwise the two seem indistinguishable. 
CONVOLVULUS ARVENSIS, L. (BINDWEED). 
With the preceding members of the genus the pollen is spher- 
ical ; with Convolvulus arvensis the grains are sub-elliptical, less 
than twice as long as broad, the surface being longitudinally trav- 
ersed by three equidistant depressions or sulci, and the entire extine 
densely clothed with short stiff villi whose free extremities are some- 
what thickened. I have not been able to trace these villous append- 
ages through the extine. 
The grains vary in size. The average seems to be, in length, 
about 5}, inch; the greatest (central) width ;1,, the villi being 
about 5,';5 inch long. Figure 15 represents the grain, a single 
sulcus showing ; figure 16 a transverse optic diagrammatic section. 
In the paper already cited from the “ Monthly Microscopical 
Journal,” Mr. Worthington G. Smith represents the pollen of Con- 
uolwulus arvensis as is shown by figure 17, which is reproduced 
from his engraving. The grain is delineated as if covered by 
rounded papille, an appearance which I have failed to observe, 
while no allusion is made to the three longitudial depressions, nor 
to the hirsute covering, which are really conspicuous in the pollen 
examined by the writer. 
