54 MR. J. P. M. WEALE ON THE FERTILIZATION OF 
Lastly I have to advert to the singular fact of the pollinia of 
other Asclepiads being often inserted in different species—a fact 
the more strange, as in Periglossum I have always found the es- 
terior pellucid margin of the pollen-mass inserted instead of the 
inner, as in most other Asclepiads; and it is on this margin that 
the rupture and protrusion of the pollen-cells takes place, which 
is the normal mode of fertilization in this plant. 
I have on many occasions found the pollen-masses of Periglos- 
sum inserted in the fissures of the anthers of this species; and 
not merely are they inserted, but the masses are disrupted and 
give out tubes which appear to penetrate the ovarium of the 
flower. 
This noticeable fact, combined with my remarks on Gomphocar- 
- pus fruticosus and G. physocarpus lead me to suspect that such 
accidents may occasionally lead to results of which we are at pre- 
sent but faintly aware, but to elucidate which a series of repeated 
and careful experiments would be requisite. 
In the first plant, out of 6 flowers open, 4 had pollen-masses 
inserted, and 2 had 4 pairs of pollen-masses extracted. If it be 
reckoned that each flower has 5 pairs of pollen-masses and 5 
fissures, it will be seen that this plant has very few withdrawn, 
—much fewer than is usual, so far as my observations go. 
Thus 6 x 5=30 pairs pollen-masses, 
4 , withdrawn, 
20 , 1n situ, 
6 x 5=30 fissures, 
6 with masses inserted, 
24 unfertilized. 
In the second plant, not reckoning that destroyed by insects, 
out of 8 flowers, 7 had pollen-masses inserted, and one had 
foreign pollen inserted, and 7 had 19 pairs of pollen-masses ex- 
tracted. 
Thus, not reckoning the foreign pollen, 
S x 5 —40 pairs pollen-masses, 
19 5 withdrawn, 
21 . in M. 
