1889.] BOTANICAL GAYETTE. • 201 



out to receive pollen. This was repeated in the case of each flower, the 

 time varying slightly. The flowers remain open three days, unaffected 

 by light or shade ; then the pure white petals begin to roll up like a 

 scroll from the outermost edge inwards, inclosing the five stamens which 

 grow opposite the petals, and leaving the others, which are opposite the 

 sepals, still exposed. After a time, the sepals fold inwards over the fer- 

 tilized ovary. The pollen is (as in the Htath family) compound, com- 

 posed of four united grains, each one having spine-like projections, and 

 showing thin oval spots on the surface. I cross fertilized the flowers, and 

 they give evidence of bearing seed.— Constance G. DuBois, Waterbury, 

 Conn. 



Observations upon barberry flowers. — In the common barberry 

 (Berberis vulgaris L.) the anthers of the sensitive stamens dehisce by 

 means of uplifted valves in such a manner that the pollen adhering to the 

 inner surface of the valve (now turned inward) is brought against the 

 rim of the large discoid stigma when the stamen is irritated. This posi- 

 tion is secured by the valvular suture extending to the top upon the out- 

 side of the stamen (the whole valve being lateral), then by contraction 

 the valve is folded inward and upward and the inner surface loaded with 

 pollen is brought facing the pistil. 



An examination of the stigma shows that there is a narrow belt of 



long stiff hairs surrounding the whole rim of the cup-shaped stigma 

 These hairs are abundantly provided with an adhesive substance, and the 

 cushion or belt of hairs occupies that portion of the top of the style 

 against which the anthers come when they bevel inward, and in an ordi- 

 nary flower this zone is soon covered over with adhering pollen. All of 

 the upper surface of the discoid stigma is covered with short papillae as 

 is also the deep cleft which extends downward into the style. In the 

 examination of a large number of stigmas not a single pollen grain was 

 found germinated in the brush of hairs, but above this, and of course at 

 a point out of reach of the stamens of that flower, pollen tubes were not 

 infrequent. 



Paper sacks were placed upon branches bearing racemes of unopened 



flowers, and all insects thereby excluded. The blossoms were examined 

 from time to time, and in all cases the pollen was abundant upon the 

 brush, but none could be seen upon the stigma proper. Out of thirty 

 racemes thus covered only four formed any fruit, and three of these ber- 

 ries were upon a branch over which the sack was defective, having a hole 

 at the top. The other case may be a case of close fertilization, or an in- 

 sect possibly worked its way into the sack from its base, where it might 

 have been imperfectly folded around the stem. The flowers not covered 

 by sacks upon neighboring branches or shrubs fruited heavily. The ob- 

 servations with microscope and the actual field experiments suggest that 

 the brush is only a means for wide fertilization.— BrRON D. Halsted, 

 New Brunswick, N. J. 



