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111 
The Fertilization of Three Native Plants.* 
By.-E.-G. Hi, 
—I.—Campanula aparinoides, Pursh. 
It is well known that species of Campanula are adapted to 
cross-fertilization by the agency of insects, the flowers being 
proterandrous. This was clearly worked out and described by 
C. Sprengel in his famous book, the pioneer of work in this line, 
published at Berlin in 1793+. The illustrations in the plates 
(Taf. 9, 11.) accompanying the letter-press are good represen- 
tations of what may be seen in species figured there, or in those 
allied to them. Hermann Miiller, in his two principal works on 
the fertilization of flowers by insects}, enters into their structure 
and adaptations with considerable detail, and with careful analysis, 
giving examples of several species and full illustrations in typical 
cases. All follow the same general plan, the individual variations 
being slight, since the species conform to a type more uniformly 
than genera usually do, as is also the case with the allied genus 
Phyteuma, The whole arrangement is very curious and interest- 
ing, being well planned to secure the designated end. Campanula 
aparinoides, Pursh, does not differ in any essential point of 
structure from the other members of the genus. The nectar, 
which is the object sought by visiting insects, is stored in a 
yellowish, fleshy disk, resting on the pistil and surrounding the 
base of the style. The disk is nearly covered by the enlarged 
bases of five filaments, termed ‘“ valves” by Sprengel, quite — 
triangular in shape in C. rotundifolia and some other species, and 
rather elongated triangular in C. aparinoides. The five free 
spaces between these “valves” or enlarged bases of the filaments, 
are themselves nearly closed by interlocking hairs, projecting trom 
the edges of the filaments.§ In C. aparinotdes there are also hairs — 
projecting from the inner side of the corolla at its base, and 
directed inwards towards the filaments. In the bud, and during 
the early stages of its development, the anthers, like a hollow 
* Read before the State Microscopical Society of Illinois, Dec. 12, 1890. 
+ Das entdeckte Geheimniss der Natur im Bau ape in der Befruchtung der 
Blumen, pp. 109-112. 
} Die Befruchtung der Blumen durch Insekten, und edie: 
§ H. Miller, Befruchtung, p. 373. 
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