POLLINATION OF FLOWERS 
671 
is of necessity of wide occurrence among 
the cone trees, and is always effected by the 
wind never by insects. It might be sup¬ 
posed that the great abundance of pollen 
would be attractive to bees, but there is no 
record of bees ever gathering it, or of flies 
feeding on it. Several species of beetles 
have been observed eating the pollen of 
pine trees. 
POLLINATION OF THE FLOWERING PLANTS OR 
ANGIOSPERMS. 
Th Angiosperms are today the dominant 
type of plant life, and cover the larger 
part of the land surface of the globe. About 
132,000 species have been described. They 
show a marvelous power of adapting them¬ 
selves to all conditions, growing in swamps, 
salt-water, marshes, rivers, ponds, and 
even in the ocean; in arid deserts and alka¬ 
line sinks; under tropic heat and arctic 
cold and at sea-level and on mountain sum¬ 
mits. They have been well called the An- 
tkopliytes or flowering plants. Many emi¬ 
nent botanists would restrict the word flow¬ 
er to this group, which has the seed en¬ 
closed in an ovary or seed vessel, and the 
pollen received on a glutinous surface call¬ 
ed the stigma. The term as thus limited 
has a very definite meaning, which can not 
easily be misunderstood, even when the 
flower is reduced to a single stamen or pis¬ 
til as among the aroids. This definition 
has also the advantage that it agrees with 
the popular conception of the word, and 
when possible for obvious reasons it is de¬ 
sirable that the definitions of the scientific 
and non-scientific public should agree. 
THE ORGANS OF THE FLOWER. 
If some common flower, as a buttercup, 
rose, or basswood blossom, is selected for 
examination it will be seen to consist of 
many small central thread-like organs sur¬ 
rounded by two whorls of leaves. The 
outer circle of leaves is usually colored 
green, and forms the calyx or cup, each 
leaf of which is a sepal. The function of 
the calyx is to protect the inner and more 
delicate organs, especially in the bud, when 
the calyx is visible. The second or inner 
circle of leaves is the corolla, or little crown, 
and the several leaves of which it is com¬ 
posed are petals. The corolla is often large 
and bright colored, but in many flowers it 
is small and greenish. When conspicuous 
the role of the corolla is to attract the at¬ 
tention of insects or birds. The two sets 
of leaves taken collectively a re termed the 
perianth. The central thread-like members 
of the flower are the stamens and pistils. 
The stamens stand next to the corolla and 
consist of slender stems or filaments, bear¬ 
ing the two-celled anthers filled with pol¬ 
len. In the center of the flower are the 
pistils. A pistil consists of three parts— 
the ovary, style and stigma; but the style, 
or stalk, is sometimes wanting. The base 
of the pistil is the ovary, or seed-case, 
which contains the unfertilized ovules or 
young seeds; the style is a porous stalk ris¬ 
ing from the ovary, at the upper end of 
which there is a glutinous receptive sur¬ 
face called the stigma. Pollination is the 
transference of pollen from the anthers to 
the stigma. If the pollen is from the same 
flower it is self-pollination; but if from a 
different flower it is cross-pollination. 
Cross-pollination between flowers on the 
same plant or between the flowers of plants 
descended from the same stock is little bet¬ 
ter than self-pollination. Cross-pollina¬ 
tion between different strains or varieties 
of the same species or between different 
species is hybridization. 
FERTILIZATION. 
Soon after a grain of pollen has lodged 
on the stigma, if the proper conditions ex¬ 
ist, it sends out a slender tube which grows 
down thru the porous style, by which 
it is nourished, until it comes to one of the 
ovules in the ovary. It enters the ovule 
by a little orifice (micropyle, meaning lit¬ 
tle gate), and there passes from the end 
of the tube a male cell,, which unites with 
an egg cell in the ovule—this is fertiliza¬ 
tion. Fertilization does not always occur 
immediately after pollination; for instance, 
the flowers of witch-hazel are pollinated in 
the fall, but fertilization does not occur 
until the following spring. 
THE FORMS OF FLOWERS. 
But there are comparatively few flowers, 
which, like the buttercup and rose, have 
all the members present, separate and regu¬ 
lar in form. In many species a part of 
the organs are wanting. The cat-tails, 
pondweeds, gTasses, and sedges have neith- 
