82 MISSOURI BOTANICAL GARDEN BULLETIN 
short, with hollow dilated base; stipules a tubular sheaf flar- 
ing into ruffle-like border. Flowers monoecious, in globular 
heads on flexible stems; staminate axillary, deep red; pistil- 
late terminal, pale green tinged with red, with long stems. 
Fruit a dry pendulous ball, solitary or rarely two on a single 
peduncle, 1 inch in diameter, composed of close-set pointed 
akenes. Preferred habitat, borders of streams and rich bot- 
tom lands. Distribution, southern Maine to north shore 
of Lake Ontario, west to Minnesota and Nebraska, south to 
Florida and Texas. An excellent shade and ornamental tree, 
especially in cities and towns. Wood is used for furniture 
and inside woodwork of houses, also for butchers’ blocks and 
tobacco boxes. 
SHADING GREENHOUSES 
On account of the intensity of the sun during the summer 
months in St. Louis it becomes necessary to apply temporary 
shade upon the roof glass of greenhouses to prevent burning 
and subsequent disfiguring of foliage, especially where exotie 
plants are concerned, such as ferns, orchids, ete., which nat- 
urally grow in shady places. With the advent of green- 
houses in Europe, green-colored glass was used for the roof 
so as to offset the rays of the sun, and although this practice 
was soon abolished because of the density of the shade dur- 
ing winter and spring, the name greenhouse was retained. 
Temporary green shading is generally used in Europe, and 
has been practiced in St. Louis at the Garden for several 
summers upon the large conservatories where the perma- 
nent plantations are housed. On the growing houses reserved 
for the production of bedding plants and floral dis- 
play material the green shading is not necessary, as such 
plants need a strong light to develop their foliage and to 
accustom them to strong sunlight when planted outside. If 
a shade is required for certain kinds of floral display mate- 
rial a white covering is used. It was particularly noticeable 
last summer during the intense heat that numerous leaves 
of orchids, especially the slipper variety, were burned by 
the rays of the sun penetrating the sides of the house despite 
the glass being ground. Consequently, for the first time, 
the sides were shaded green as well as the roof. 
