CCI.— THE MARSH ANDROMEDA. 
Andromeda Polifolia Linne. 
T HE Heath Family or Ericaceae, represented by this and the five following 
Plates, is a group of considerable variety, seeing that it comprises some fifty 
genera and more than thirteen hundred species. They are, however, more 
prominent in the vegetation of the globe than these figures suggest, from the fact 
that some of them grow socially, so that large tracts of country are covered by one 
or two species and are known from them as “ heaths.” Represented in most parts of 
the globe, except in desert regions and the hot moist intertropical areas, they are 
specially abundant in certain countries from which many species with beautiful 
flowers have been brought to our gardens. Thus many of them are known as 
“ Cape Plants,” whilst other genera are so distinctively North American as to 
have given rise to the name of “American garden” for the peaty borders in 
which they are cultivated. Their geographical distribution is of great interest, 
since they seem — during recent geological periods at least — to have radiated from 
very different centres, from Northern polar regions and from South Africa alike. 
Most of them are perennial evergreen, wiry undershrubs, shrubs, or trees, 
with leathery and often rigid, opposite or whorled, simple, entire leaves. The 
slow-growing, wiry habit and the frequently small size, inrolled edges and adpressed 
position of the leaves, are the expression of the xerophytic character of the Family 
as a whole. Living, as most of the species do, either in poor porous sands, or 
thin-soiled mountain-sides, or in peaty soils rich in humus, but often acid, they 
are almost all under the necessity of economising their water-supply. Thus the 
leathery leaves, to diminish transpiration, have a thick cuticularised upper epidermis ; 
their stomata are confined to the under surface and are protected from the sun’s 
heat by the extensive inrolling of the edges ; while there is sometimes a special 
water-storing tissue in the interior. 
The flowers are mostly in bracteate, racemose inflorescences, perfect, and 
polysymmetric, either tetramerous or pentamerous, with two whorls of stamens, a 
honey-secreting disk, and a simple style. The corolla is usually bell- or barrel- 
shaped : the anther-chambers open by pores at their apex : the pollen-grains are 
united in tetrads ; and there are often special appendages to the anthers connected 
with the mechanism of insect-pollination. Most of our British representatives of 
the Family have pendulous flowers, adapted for pollination by bees hovering below 
them. The insect first touches the projecting stigma, parting with pollen that may 
be on its head or back, and then, probing for the honey at the base of the bell-shaped 
corolla, inevitably touches the stamens or their projecting awns, and so brings down 
a shower of the aggregated pollen-grains from the terminal pores of the anthers. 
Drude divides the Family into four Sub-Families : — the Rhododendroide # , 
including the Rhododendrons, Azaleas, and Kalmias, which have a deciduous corolla, 
