XXxil INTRODUCTION TO BOTANY. 
frequently to enable plants usually annual to live through the 
winter. Flowers in a maritime variety are often much fewer, 
but not smaller. 
The luxuriance of plants growing isolated in a rich soil, and the 
dwarf, stunted character of those crowded in poor soil are well 
known. It is also well known how gradually the specimens of 
a species become stunted as we advance into the cold, damp 
regions of the summits of high mountain-ranges, or into high 
northern latitudes ; and yet it is very frequently for want of 
attention to these circumstances that numbers of false species 
have been added to enumerations and Floras. Luxuriance en- . 
tails not only increase of size of the whole plant or of particular 
parts, but increase of number of branches, or leaves, or leaflets 
of a compound leaf; or it may diminish the hairiness of the 
plant or induce thorns to grow out into branches, etc. 
Capsules which, while growing, lie upon or close to the ground, will 
often become larger, more succulent, and less readily dehiscent, 
than those which are not so exposed to the moisture of the 
soil. 
Herbs eaten down by sheep or cattle, or crushed underfoot, or 
burnt over, or otherwise checked in their growth, or trees or 
shrubs cut down to the ground, if then exposed to favourable 
circumstances of soil and climate, will send up luxuriant side- 
shoots, often so different in the form of their leaves, in their 
ramification and inflorescence, as to be scarcely recognizable for 
the same species. 
Annuals which have germinated in spring and flowered without 
check, will often be very different in aspect from individuals 
of the same species, which having germinated later, are stopped 
by summer droughts or the approach of winter, and only flower 
the following season upon a second growth. The latter have 
often been mistaken for perennials. 
Hybrids, or crosses between two species, come under the category 
of anomalies from a known cause. Frequent as they are in 
gardens, where they are artificially produced, they are probably 
rare in nature. Absolute proof of the origin of a plant found 
wild is of course impossible; but it is pretty generally agreed 
that the following particulars must always coexist in a wild 
hybrid. It partakes of the characters of its two parents; it is 
to be found isolated or almost isolated, in places where the two 
parents -are abundant; if there are two or three, they will 
generally be dissimilar from each other, one partaking mor : of 
one parent, another of the other; it seldom ripens good seed ; 
it will never be found where one of the parents grows alone. 
Where two supposed species grow together, intermixed with 
numerous intermediates bearing good seed, and passing more or 
less gradually from the one to the other, it may generally be 
concluded that the whole are varieties of one species. The 
beginner, however, must be very cautious not to set down a 
specimen as intermediate between two species, because it 
appears to be so in some, even the most striking characters, 
such as stature and foliage. Extreme varieties of one species 
are connected together by transitions in all their characters, 
but these transitions are not all observable in the same speci- 
men. ‘The observation ofa single intermediate is, therefore, of 
little value, unless it be one link in a long series of intermediate 
forms, and, when met with, should lead to the search for other 
connecting links. 
