lo-t 



hering to its abdomen. A.s the bee advances upward toward the 

 tube of the calyx, he treads upon the inflated sacks at the base of the 

 anthers, which yield to the pressure and, acting like a bellows, force 

 through the minute pore a jet of the minuter pollen directly upon 

 the rear or side of the intruder, but directly away from the stigma. 

 I have seen an humble-bee upon a flower, pressing with his feet on the 

 bellows, but, of course, could not get near enough to see the play of the 

 pollen. It may easily be seen, however, by touching the bellows 

 with a blunt point, when a surprising quantity of pollen will be thrown 

 upon the instrument. A sharp point, like that of a pin, would be 

 apt to perforate ^id spoil the delicate bellows. When touched in 

 this way, it will be noticed that simultaneously with the jet of pollen 

 the anther springs forward as if to aid the expulsive force, and then 

 immediately springs back. In fact, my first impression was that it 

 was this jerk which discharged the pollen. It is easily accounted 

 for by the disposition of the parts as I have described them. The 

 spur of the connective seems to act as a buttress to keep the anther 

 in its tilted position. 



It is evident that here is a very perfect contrivance for securing 

 cross-fertilization, at least to a considerable extent. Though each 

 plant of Rhexia produces a number qf flowers, yet only one or two 

 are usually in bloom at the same time, and these probably in differ- 



ent stages of advancement. The petals, which are the signals in- 

 viting insects, last but for a day or perhaps even a shorter time. 



There are other points in the structure of Rhexia ; the glandu- 

 lar hairs on the petals as well as other parts of the plant ; the wing- 

 angled stems, etc., which would repay study, if one had the plants 



accessible. For some of these observations I am indebted to my 

 associate, Mr. Gerard. • 



In the case of Cassia Marilandica, I have watched an humble-bee 

 hugging an anther, and apparently, so to speak, milking out the pollen. 



W. H. L. 



97. The Herbaria and Botanical Libraries of the United 



States. VIU, — The Herbarium of Cornell University numbers 

 not far from 18,000 species. The larger part of the collection is 

 made up of the herbarium of the late Horace Mann, Jr., which was 

 purchased by President White and presented to the University soon 

 after its opening in 1868. This is a general collection, but is especially 

 rich in Sandwich Island plants. The principal additions since made 

 include the Brazilian plants collected by the officers and students of 

 the University in their expedition to South America in 1870; the 

 Western United States plants collected in connection with the C.ov- 

 ernment surveys of the Western Territories; small collections, some 

 of them European, donated from various sources; and a very nearly 

 complete collection of the plants growing in Central New York, com- 

 prising especially the flora of Cayuga Lake Valley, A full set of the 

 latter, numbering about 1,300 species of phaenogamia and vascular 

 cryptogamia, and known as the "local herbarium," is kept separate 

 from the main collection for the convenience of students makin^'' a 

 somewhat careful study of the whole or of some group of the lo1:al 



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