Fig. 217). They very often have special structures, e.g., 
spurs or other modifications of parts, to form or to store 
up nectar. They also possess a pleasant scent, and 
attract numerous insect visitors by the varied induce- 
ments they offer. Some insects (e.g., Bees) also visit 
flowers to eat or to collect pollen, or to carry it away as 
food for their young progeny. Whatever the reason of 
-~ 
Fig. 217. EXPANDED BLOSSOM OF PEa—v, Vexillum ; al, Ale, with 
-Carina between, ` 
the visit, the insect generally becomes dusted with pollen, 
which it transfers to the stigma of the next flower of 
the same species that it enters. The pollen in entomo- 
philous flowers is less abundant than in the anemophilous 
ones; and the grains very frequently bear ridges or 
- spines, so as to stick more readily to the insect, or they 
are joined together in groups of four or more, as in 
A, Pollen Masses, &c.—po, Pollinia ; e, Candicle ; vd, Viscid Disk : 
: Rostellum ; ir, Lip of Rostellum. È 
Granules (much magnified), held in packets by thin, 
Heaths and Orchids (see Fig. 218). The masses are 
furnished, in Orchids and a few other plants, with 
Special contrivances to favour adhesion to the insect’s 
— body, and afterwards to place them in the best posi- 
tion to touch the stigra of the flower next visited 
— in, p nob e tee’ — 
are r the ianth 
and the anthers burst in such a way as to let free the 
pollen in the position most likely to insure its 
. bei 
dusted on to the insect. The stigma or stigmas d aA 
often project beyond the perianth, and are —— 
small and rounded, or linear, down one side 
_ The surface is usually covered with a eu —— 
_ cells, which secrete a viscid fluid, and in this the pollen 
grains are caught when any part of an insect’s bod 
dusted with them touches the stigmatic surface. The 
pie pa — ge nourishment from this fuid, and 
are lated to emit pollen tub i 
Sao ar pol es between the cells of 
: ; F: jili: ; or “all a. 
_cleistogamous flowers, and a few others tga 
— or “ autogamy.” — 
and that the i 
x e stigmas are arti- 
180 THE DICTIONARY - OF GARDENING, 
Pollination—continued. 7 Pollination—continued. 
-various Orchids. 
disadvantages of allogamy are that it entails on the plant 
a greater production of pollen, as by far the greater part 
neyer reaches a stigma; and, even with this, many 
stigmas may remain unpollinated, and no seeds be pro- 
duced in these flowers. Moreover, such flowers‘as have 
been specially adapted for fertilisation by a certain kind, 
or kinds, of insects, may, in absence of these agents, 
remain unpollinated and barren. This occurs with certain 
greenhouse plants, which are fertile if Pollinated arti- 
ficially, but, without human aid, remain barren, e.g., 
Under Nectary and Orchid Ferti- 
lisation several adaptations of flowers to benefit — 
by visits of insects will be found discussed, and only 
one or two examples need here be added to those 
referred to under the above headings. By far the, 
most interesting examples of adaptations for Pollination 
of the stigmas with pollen from another flower, are met 
with among entomophilous flowers. Many of these are — 
suited to benefit by the visits of Beetles, Sawflies, and 
other insects, which do not possess a long proboscis; 
hence, the nectar or p that attracts them is situated 
almost on the surface, or, ‘at least, is easily accessible, 
Fie. 219. ‘STRAWBERRY PLANT IN FLOWER, showing the numerous: 
short Stamens, readily accessible to Insects. 
But even among open and regular flowers examples — 
occur in which very perfect adaptations for cross-poll 
ee oe Kalmia latifolia (see Fig. 220) may 
be selected as an example. In this plant, the style 
in the middle of the flower, bearing the small stigma | 
ite tip. There are ten stamens, curved as shown in thé 
figure, so that the anthers are situated each in a small 
— in the corolla. In these pouches they remain till 
e filaments are touched with a little force, and, 
