AN ENCYCLOPEDIA 
OF HORTICULTURE. 181 
Pollination—continued. 
flowers are protected under net or glass, they wither 
and fall without the anthers getting free or the stigma 
being Pollinated, and the flowers remain barren. But, 
in the natural condition, the flowers are freely visited 
by various Bees, and other insects, which usually alight 
on the style, and, in sucking the nectar, come into con- 
tact with the filaments, and set free the anthers one by 
one. The filaments straighten themselves, and the pollen 
LPF ig 
Fic. 220. DETAILS OF KALMIA LATIFOLIA, 
ded Flower—ap, Anther — B, Section of Expanded 
ver ae, ap, Anther Pockets . 
Pollen Grains in Shower ; ca, Cates: C, 
—ap, Anther Pocket. D, Stamen, more- ———— 
Anther ; po, Pores ; pg, Pollen Grains ; J, Filament. | 
A, E: 
is thrown out of the anther, from two kiall holes at the 
tip (see Fig. 220, D), against the insect’s body, to be thus 
transported to the stigma of another flower. Such 
flowers as characterise the Labiate, the Orchidew, and 
the papilionaceous Legwminose, in possessing bilateral 
symmetry, are among the peculiarly entomophilons 
types, especially when the nectar is so placed as to be 
accessible only to insects possessed of a long proboscis, 
Pa 
Fig. 221. POLLINATION OF ORCHID. 
A, Flower of Orchis Morio (Sepals, two Petals, and side of Spur 
removed), with Hive Bee sucking Nectar—a, — po, 
Pollinium ; r, Rostellum ; st, Stigma — view): lium ; * 
“ov, Ovary ; n, Nectary ; br, Bract. B, Head of Bee, carrying 
(po) Pollinium—an, Antenne. : ‘ 
e.g., Bees (see Fig. 221). In addition to this, in some 
e.g., in Antirrhinum (see Fig. 222), the corolla is closed by 
the lower lip, which is pressed against the upper one, 
and excludes all but insects heavy enough to —* it, 
e.g., Humble Bees. In the strictly entomophilous flowers, — 
_ very striking adaptations to favour the visits of insects 
_of certain groups, or even of certain species, and to 
“exelude other insects, are often met with. Bat the field 
is so wide, P girs ae 
d far exceed a pest the section 
Pollination—continued. 
space here available. Readers are therefore referred to 
the works noted above, and their attention is called 
to a subject of the utmost interest in itself, and of 
great practical value in its relations to hybridising 
Fig. 222. FLOWER OF ANTIRRHINUM ORONTIUM. 
plants, and to the development of new races of value 
for their. beauty, or for other properties suited to com- 
mend them to gardeners and to amateurs. 
POLLINIA. Pollen-masses. 
POLY. In Greek compounds, this signifies numerous; 
e.g., Polycotyledonous, having several cotyledons. 
POLYACTIDIUM. Included under PRIER 
POLYADELPHIA. A Linnæan artificial order, 
characterised by having stamens in several phalanges. _ 
POLYALTHIA (from polys, much, and althecis, 
healthy; alluding to supposed properties of the plant). 
ORD. Anonacee. A genus comprising about thirty species — 
(including twenty-five which are sometimes classed with 
Guatteria) of stove or greenhouse trees or shrubs, natives 
of tropical Asia, one being Australian. Flowers solitary 
or fasciculate, axillary or opposite the leaves ; sepals 
three, valvate or rarely loosely imbricate ; petals six, 
bi-seriately valvate, flat, almost equal, ovate or narrow. 
Leaves oblique, penniveined. The two species described 
below are the only ones worth mention. They are stove 
trees. For culture, see Guatteria. 
* -like) uncles axi 
— — aR gpg —— Peano k 
h. 60ft. East Indies, 1820. 
P. suberosa (corky-barked) 
three inner ones whitish ; peduncles nearly opposite the leaves, 
one-fiowered. l. oblong, acute, smooth. h. 30ft. India, 1820. 
POLYANDRIA. A Linnzan class, having flowers _ 
with an indefinite number of stamens. ae 
POLYANTHES. A synonym of Polyxena (which - 
see). aw 
POLYANTHUS. A garden race of Primula, — 
bably derived from a cross between the Primrose ana 
Cowslip. The Polyanthus has been in cultivation for | 
many years, and has proved itself one of the most 
pan of florists’ flowers. The attention, however, now 
towed on it is much less than at an earlier period — = 
of its history, and the varieties raised are — less 
numerous. Good varieties, that were once procurable, — 
are now lost to cultivation, and those of the present 
day are not generally considered of equal merit—at 
least, for exhibition purposes. As a hardy garden 
plant, the Polyanthns is likely to remain a favourite, 
and deservedly so, for planting on rockeries, in mixed 
borders, and in spring flower-beds, The vigorous-growing 
varieties, which may be readily raised from seed, are _ 
admirably adapted for naturalising in pleasnre-grounds 
along the sides of walks, &c. Florists’ rules regarding 
the flowers of a Polyanthus, and the recognised qualities 
exhibited in them, are very rigid; it is, however, un- 
necessary to follow them too closely, unless the flowers 
are required for exhibition. For the last-named purpose, 
known as — is most — the 
Ji., three outer petals greenish, the _ 
