The genera of South African plants : arranged according to the natural system / by William Henry Harvey.
- William H. Harvey
- Date:
- 1868
Licence: Public Domain Mark
Credit: The genera of South African plants : arranged according to the natural system / by William Henry Harvey. Source: Wellcome Collection.
48/556
![frequently to enable plants usually annual to live through the vunter. Flowers in a maritime variety are often much fewer, but not smaller. The luxinaanco 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 niunbcrs 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 loaves, or leaflets of a compoimd loaf; or it may diminish the hairiness of the plant or induce thorns to' grow out into branches, etc. Capsules wliich, while growdng, lie upon or close to the groimd, will often become larger, more succulent, and less readily dehiscent, than those which arc not so exposed to the moisture of the soil. Herbs eaten down by sheep or cattle, or crushed imdorfoot, or burnt over, or otherwise checked in their growth, or trees or shrubs cut down to the ground, if then exposed to favom-ablo circumsbinccs of soil and climate, will send up luxuriant side- shoots, often so dilforont in the foirn of their loaves, in their ramifleation and inilorosconco, as to bo scarcely recognizable for tlio same species. Annuals which have germinated in spring and flowered without check, will often bo very dift’eront in aspect from individuals of the same species, wliich having gorminiitod later, are stopped by summer droughts or tho approach of Avintor, and only flower tlio following season upon a second growth. Tho latter have often been mistaken for perennials. I lybrids, or crosses between two species, come under tho oatogory of anomalies from a known cause. Frequent as they are in gardens, whore they arc aidiflcially produced, they are iirobalily rare in natm-o. Absolute proof of tho origin of a plant found wild is of course impossible; but it is pretty generally agreed that tho following particulars must always coexist in a wild hybrid. It jiartakos of tho characters of its two parents; it is to bo found isolated or almost isolated, in places where the two parents are abundant; if there are two or throe, they will generally bo dissimilar from each other, one partaking mor) of one ])aront, another of the other; it seldom ripens good seed; it will never bo found where one of tho parents grows alono. ^Vl^cre 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 bo concluded that the whole are varieties of one species. The beginner, however, must bo very cautious not to set down a specimen as intermediate between two species, because it appears to bo 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, blit these transitions are not all observable in the same speci- men. The observation of a single intermediate is, therefore, of little value, unless it bo one link in a long series of intermediate forms, and, when met with, should lead to tho search for other connecting links.](https://iiif.wellcomecollection.org/image/b28117347_0048.jp2/full/800%2C/0/default.jpg)
