Trelease.] 
424 
[March 15, 
disturbed, pollen may not reach the stigma, though the anthers 
dehisce immediately over it. A violent shake, however, while a 
stamen is over the stigma will almost certainly cause pollen to 
fall upon the latter. At this time, to be sure, it is unreceptive, but 
it is possible for the pollen to remain upon it in fit condition to 
fertilize the ovules until its maturity. There is also the possibility 
that if the flower has not been visited, a jar may at any time 
throw pollen, remaining on the erect stamens, upon the stigma, 
even after the latter is receptive, and as before the pollen may 
still be effective. A few experiments to test these possibilities 
gave no positive results, although in some instances pollen was 
undoubtedly placed on the stigma. At all events the structure 
and development appear to be very efficient means of securing 
crossing if the flowers are visited by insects ; wdiile it may be 
shown that the pollen is not self-impotent, and that self-fertilization 
occurs when crossing has not been effected in season. 
Ericaceae. 
Erica Wilmorei ? (S. Africa). — In this pretty heath the flow- 
ers are crowded along wand-like branches. Each is about 2 cm. 
long, tubular, with the four lobes of the corolla slightly spreading, 
figs. 21-22. Their color is pink at the base, gradually growing 
paler until at the mouth it is white. Nectar is secreted in large 
quantities by a lobed hypogynous gland, fig. 26, and is protected 
from creeping insects by the pubescence of the corolla. The 
eight stamens are inserted below the nectar gland and reach 
nearly to the mouth. Each anther is two-celled, the cells opening 
by large pores extending from the tip down the side. Contiguous 
anthers are united by the margins of their pores fig. 25, so 
that when the flower expands they form a closed tube about the 
style, not in the axis of the flower, but above it, figs. 22-24. 
At this time the anthers are dehiscent, so that if they were not 
coherent by the margin of their pores the pollen would be exposed 
as in Azalea, etc. Their union is not mere contiguity, but they 
adhere in opposition to a considerable elastic tension of the fila- 
ments, as is seen by their immediate separation when the union 
is broken in fresh flowers. The stigma, situated just beyond the 
end of the anthers, is immature at this time. Later the style 
commonly elongates a little, and the stigma grows moist and 
receptive. 
