Miscellaneous. A487 
fertile it is fair to assume that it must be arranged for self-pollina- 
tion. In Asclepiadacese, with the large majority of the flowers 
barren, we may theoretically assume insect agency,—with many 
abundantly fertile Apocynacese we may assume self-fertilization. 
I have already shown that the Madagascar periwinkle, Vinca 
rosea, with every flower fertile in American gardens, is a self- 
fertilizer. Another of the same order, Amsonia Taberncemontana 
(the form known as A. salicifolia, Pursh), is abundantly fertile. I 
watched the flowers this season, satisfied that they would be found 
arranged for self-pollination. The plants proved, as usual, abun- 
dantly fertile. On one panicle there were twenty-nine pairs of 
follicles that matured; there were many others that had been 
evidently fertilized, but failed to reach maturity through lack of 
nutrition, : 
Showy as the blue flowers are, and we might suppose, in view of 
prevailing speculations, made so in order to be attractive to insects, 
the arrangements are such that no insect, not even the ubiquitous 
thrips, can gain entrance to the nectary. ‘The mouth of the tube is 
so densely matted with hair that Kuue clausa is the term used in 
the description of the species by Latin authors. If a pollen-clothed 
tongue were thrust through the mass it would be thoroughly 
cleaned, and in like manner the flower’s own pollen would be 
brushed back when the insect withdrew its tongue. But a greater 
difficulty presents itself. The capitate stigma with its surrounding 
rim completely fills the upper portion of the tube. There is no 
space for an insect’s tongue to get past the stigma. But even could 
this rubicon be passed, a dense mass of hair presses close against 
the style, and the most powerful insect known to the writer could 
hardly force a passage. The entrance of insects is completely 
blocked. To provide for pollination the anthers curve over and 
rest on the stigma, and the pollen on ejection from the anthers can 
do no more than cover the stigma. 
In many plants which have flowers that are generally fertilized 
by their own pollen the arrangements will often permit of pollina- 
tion from some other; but in the case of this Amsonia nothing but 
self-pollination is possible. 
To those who may not have flowers for comparison the figure of 
this plant in ‘ Botanical Register,’ pl. 151, will aid in making some 
of the above-noted points “clear. —Proe. ‘Acad, Nat. Sc. Philad. 
March 29, 1892, p. 162. 
