206 MR. J. SCOTT ON PASSIFLORA, DISEMMA, AND TACSONTA. 
unions of the three individual plants of the P. alata one with 
another, and with distinct species. Of the four pure unions given 
in lines 15 to 18 inclusive of the Table, one alone is fertile; thus 
the female element of A 1 can be fertilized by the male ele- 
ment of A2, but the male element of the former fails to effect 
fertilization on the female element of the latter. Nearly similar 
results are afforded in the reciprocal experiments with A 1 and 
4.3, in which we have no fertile unions, though we have clearly 
symptoms of a conjunctive susceptibility in the setting of three 
of the ovaries (vide Table, lines 17 & 18). Again, the male ele- 
ments of two of these plants of P. alata, A 1 & 2 respectively, 
fertilize the female element of the P. racemosa; and the male 
element of A 1 will fertilize two distinct species of the nearly 
allied genus Disemma (vide Table, lines 20 & 22). Though we 
have here proofs of the potency of the male element of these 
three plants of the P. alata and of the goodness of the female 
element of one of them, they nevertheless all proved utterly im- 
pregnable by their own pollen (vide Table, lines 31, 32 & 33). 
Fourthly, we have the curious results of the unions between 
P. holosericea and P. manora (vide Table, lines 24 & 25), in which 
the male element of the latter effects the perfect development of 
the ovaries of the former, while it utterly fails in effecting the 
slightest development of the seeds. Again, in the converse ex- 
periment the male element of the P. holosericea is almost im- 
potent on the female element of the P. manora, as only in one 
instance did a single ovary set, and this did not continue swelling. 
When these two species are fertilized with their own pollen we 
find utter impotence, as shown in lines 34 & 35 of the Table, for 
in a large number of flowers thus fertilized in no single instance 
did an ovary set. 
Lastly, the male element of the 7ucsonia mollissima effectively 
fertilizes the female element of the Z. pinnatistipula, while in the 
converse experiment, though the pollen of the T. pinnatistipula 
applied to the stigmas of T. mollissima effects the perfect deve- 
lopment of the ovarian coats and the hard or spermodermie cover- 
ings of the seed, it utterly fails in effecting the development of 
the embryo and albuminous matter. Again, T. pinnatistipula, 
though in general very insusceptible to own pollinie influence, 
does in rare cases, as shown in previous details, yield a fine 
plump ovary filled with apparently good seeds. On examination, 
however, I have invariably found that the spermoderm and albumen 
had alone been developed, while the embryo was entirely absent. 
