MR. T. H. CORRY ON ASCLEPIAS CORNUTI. 185 
knowledge of the mode in which the fertilization of the Asclepiad flowers is effected. 
In the blossoms of seven species of the genus Asclepias which he examined, he several 
times detected the fact that one of the pollinia was removed from the anther-cell, and 
remained no longer fixed by the descending “ process” to the stigmatic corpusculum, 
but was immersed, and hidden from external view, in one of the fissures between the 
projecting anther-alæ, while in most cases it was separated from the stigmatic corpus- 
culum to which, when 2% situ, it had been attached. Не further observed a connexion 
between the gibbous part of the more convex edge of the pollinium (which, when the 
pollinium lies i» situ in the anther-cell, is placed on the side furthest from the ајаг 
fissure) and that point where the apex of the tube formed by the combined staminal 
filaments is joined* to the surface of the base of that angle of the style-table which 
corresponds to it. This point is in close contact with the pollinium. The connexion 
alluded to is produced by the rupture of the pollinium and the production of a great 
number of delicate pollen-tubes, which, forming a fasciculus, pursue a course which 
runs, in a manner hereafter more fally described, directly inwards along the base of the 
style-table to the apices of the styles. From this it will be gathered that Brown had 
found the truly stigmatic portions of the table. Aware, as he was, of Sprengel’s obser- 
vations on the mode of extraction of the pollinia by insects (since he refers to the portion 
of the latter’s work in which they are contained), Brown evidently believed :— 
1. That the pollinia must be extracted by means of an insect ; and 
2. That, when so extracted by this agent, they were applied by it to a distant part of 
the same or a different flower t, and were no doubt brought by means of insects, the 
assistance of which he regards as “absolutely necessary " f to the position in which he 
afterwards found them, viz. within the alar chamber and in contact with the base of the 
style-table 9, where the truly stigmatic portion lies. 
Since he further remarks that “the prevailing form of inflorescence in Asclepiadee is 
well adapted to this economy [of pollination], for the insect so readily passes from one 
corolla to another that it not unfrequently visits every flower of the umbel ” ||, we may 
infer that he believed that these flowers were usually not self- but cross fertilized. 
Brown, however, seems to have been ignorant of the movements which the pollinia 
undergo after their extraction, or, if he was aware of their existence, to have attached no 
value to them. Nor did he understand the precise method in which pollination was accom- 
plished by the insect, and he does not mention having ever directly observed the process. 
The actual extraction of the pollinia by the feet of insects, and their subsequent inser- 
tion by the same agency into the fissures of the alar chambers, was for the first time 
observed by Frederico Delpino, in 1865, in the flowers of Araujia albens, б. Don є. This 
observer drew attention to the circumstance that identically the same mechanical con- 
ж This is Brown’s expression, Ав to its strict accuracy, vide hereafter, on p. 201. 
t Vide note on p. 522, Misc. Bot. Works, vol. i. + Ibid. vol. 1. p. 542. 
§ “Style” in Misc. Bot. Works, vol. i. p. 527: obviously a misprint. || Mise. Bot. Works, vol. i. p. 717, note. 
€ ‘Relazione sull’ apparecchio della fecondazione nelle Asclepiadee, «с., Torino, 1865. ‘Sugli apparecchi della 
fecondazione nelle piante antocarpee,’ Firenze, 1867, especially pp. 6-15. ‘Би?’ opera La distribuzione dei sessi nelle 
piante e la legge che osta alla perennità della feéondazione consanguinea, del Prof. Е. Hildebrand,’ Milano, 1867 ; 
especially pp. 24-25. ‘Ulteriori osservazioni sulla dieogamia nel regno vegetale, Milano, 1868-1869, especially 
pp. 224-228 & 243 (Ceropegia elegans), Also in * Atti della Società Italiana di Scienze Naturali in Milano,’ vols. xi. & xii. 
