90 



NATURE 



{Dec. 3, 1874 



each of these particulars the genus Aloe is no exception 

 to the general rule. Many of the species are well known 

 in cultivation, but all agree in having fleshy elongated 

 evergreen leaves, and thick erect spikes of yellow or red 

 flowers. Medicinally, many species (and possibly all 

 might be) are of importance as yielding a well-known 

 bitter drug, which is simply the juice exuded from the 

 leaves when cut, and boiled down to a solid consistence. 



The species of Aloe are probably only really indige- 

 nous in Southern and Eastern Africa. A. vulgaris is 

 now, however, found widely distributed along the Medi- 

 terranean and in the East and West Indies, where it is 

 cultivated as the source of the Barbados and Curagoa 

 aloes.* A. indica, Royle, is doubtless a slight variety. 

 Dr. Stewart mentions it as being occasionally cultivated 

 throughout the Punjab, and says that the pulp of the 

 leaves is eaten by poor people and in famines.f Accord- 

 ing to the same writer, the Aloe mentioned by Masson in 

 the Punjab is a palm [Cliamcrmps Ritchiana).X A. litto- 



ralis, Konig, found at Cape Comorin, is believed to 

 be a form of A. vulgaris, altered by the circumstances 

 of its situation. The habit of growth in the genus 

 varies considerably. Mrs. Barber, a well-known South 

 African naturalist, gives the following account of the 

 part they play in the physiognomy of the native vege- 

 tation :— 



" The genus Aloe, Linn., has a wide range in this 

 country, its numerous species occurring in all rocky 

 localities throughout the land ; wherever rocks are found 

 there are the Aloes also, cropping out (if 1 may be 

 allowed the expression) with the geological formations of 

 the country, as if they formed a part of them, decorating 

 each knoll and cliff with their gay blossoms in great pro- 

 fusion and variety, from the gigantic Aloe of the Trans - 

 keian territory, which attains the height of sixty feet, and 

 the tall, graceful, wood Aloes, to the sturdy, stout-built Aloe 

 of the chff, and the minute lizard-tail-like species that are 

 scattered among the grass, each filling its peculiar locale 



FiG. I. — Ahe dichotoma^ Linn., from Namaqualaad. 



to complete the character of the landscape, and to render 

 it truly South African in appearance." § 



It may be well to mention that the true Aloes of the 

 Old World have nothing whatever to do with the so-called 

 " American Aloe." This is a species of Agave, a genus 

 indigenous to Mexico and South America. The habit of 

 the two genera is in many respects curiously similar, and 

 they afl'ord a striking instance of " homoplasy " — of the 

 assumption by organisms essentially differing in them- 

 selves, of externally similar forms, when exposed to similar 

 external conditions. .lloe commonly flowers laterally, 

 and the growth of its main axis is therefore not arrested ; 

 Agave, as is generally known, flowers from its central bud, 

 and consequently dies afterwards. Aloe is Liliaceous 

 with a superior ovary ; ylgave is Amaryllidaceous, with 



* Fliickiger and Hanbury's **Pharmacogr.iphia," p. 6i6. 



t " f unjab Plants," p. 232. } Loc. cit., p. 242. 



§ Journ. Roy. Hort. Soc. New Series, vol. ii. p. So. 



Fig. 7:.— Aloe BarUra; Dyer, rom Kaflraria. 



an inferior one. But Aloe, as we have seen, has passed 

 to the New World, and Ai^ai/e is quite as much at home 

 now in the Old World as its representatives are. 



One is at first sight hardly prepared to hear of Aloes 

 assuming the dimensions of trees. That they do so is, 

 however, quite certain, though our knowledge of the 

 arborescent species was, till quite lately, extremely imper- 

 fect, and is, indeed, still far from complete. I collected 

 together all the material I could get access to in a paper 

 published in the Gai-deuer's Chronicle for May 2 of this 

 year. My present object, besides that of calling the 

 attention of the readers of N.-vruRE to these very remark- 

 able plants, is to correct a rather important error into 

 which I find that I have fallen respecting them. 



In point of fact, it is now pretty clear that the west and 

 east coasts of South Africa each possess one endem ic 

 Tree- Aloe. That of the west, where it is distributed from 

 Walvisch B.\y to Chnwilliam, is Aloe'dichotomi, Linn. 



