1897 | ; ABSTRACTS OF BOTANICAL PAPERS 189 
out of the micropyle, the only similar case known being that of 
Croton flavens. 
J. H. Scuuettre: Contributions on wild and cultivated roses of 
Wisconsin and bordering states — Read in abstract. 
Fanny E. Lancpon: Development of the pollen of Asclepias 
Cornuti—In this study the order of cell formation has been 
verified by nuclear figures, thus removing all doubt with regard 
to successive changes. The order of development differs from 
the account given by Corry, the only previous writer, in the fol- 
lowing particulars: (1) the archesporium, asin most dicotyledons, 
is composed of a layer of cells, and not of a single column of 
cells, as stated by Corry; (2) the tapetum from an early stage is 
composed of two to several layers, instead of a single layer; (3) 
Corry states that the wall of the tapetum next to the pollen 
becomes chitinous, and that this changed wall forms the outer 
wall of the pollinia, while the latter is found by the present writer 
to be derived in part from a secretion from the tapetum and in 
part from the changed outer walls of the pollen cells. The cells 
of the tapetum undergo remarkable changes during the develop- 
ment of the pollen, and probably function as glandular tissue, 
manufacturing a secretion which is to serve as protection to the 
pollen, rather than “breaking down.” 
Cuarves E, Bessey: Some characteristics of the foothill vegeta- 
tion of western Nebraska.—The foothill region is an elevated plain 
1200 meters above sea level, upon which are Pine ridge on the 
north, 1500 meters above sea level, and Cheyenne ridge on the 
south, 1700 meters above sea level. Upon Cheyenne ridge occur 
considerable bodies of trees, mostly pines, with red cedar, box 
elder, and others. The Box butte plains are covered with a uni- 
form grass formation. 
H. F. Osgorn and E. B. Poutton: Organic selection.—Sug- 
gestions regarding the harmonizing of Darwinism and Lamarck- 
ism proposed by Professor Osborn were criticised by Professor 
Poulton. 
James B. Pottock: Mechanism of root curvature.— From 
experiments continued during two years it is held to be demon- 
