248 SCIENCE OF AGRICULTURE. Part II. 



been known to protmdo both buds and blossoms even in the month of November. Some plants, however, 



blow only in the winter as in the case of the laurustinus and arbutus unedo ; while others blow only in 



the night, and refuse to expand their petals to the light of the sun. Such is the case of the cactus grandi- 



florus, that produces one of the most magnificent of flowers ; but blo ws only m the night ; and^ hence 



known also by the appellation of the night-blowing cereus. Some j^^tlJI^^\J2S6 



plants, such as the ferns, aigs, and fungi, are altogether destitute 



of conspicuous flowers ; and are hence called Cryptognmons ; but 



in this respect the fig is perhaps the most singular. The flowers, 



which in other cases uniformly precede the fruit, are in this case 



concealed within what is generally denominated the fruit ; as may 



be proved by cutting open a green fig {Jig. S35.) by means 'of a 



longitudinal section passing through its axis. Great numbers of 



flowers are then discovered lining a sort of cavity in the axis 



of the fruit ; and hence what is called the fruit or fig, in common 



language, is rather the receptacle of the flower than any thing else. 



Most plants have their flowers furnished both with stamens and 



pistils and are hence hermaphrodites; but there are also many genera that have the stamens in one 



flower and the pistils in another, both on the same individual ; these are denominated Moncccious plants, 



and are exemplified in the oak and hazel. Other genera have the flowers with stamens on one plant, and 



the flowers with pistils on another ; these are denominated Dioecious, and are cxemphfied in the hop and 



willow. Others have flowers of all the previous kinds on one and the same plant ; these are denominated 



Polycramous, and are exemplified in the genus Atriplex. 



1585. The fruit. The anomalies of the fruit may aflfect either its number, figure, color, or appendages. 

 The common hazel-nut produces in general but one kernel in one shell ; but in the course of opening a 

 considerable number, you will now and then meet with one containing two or three kernels in a sliell. 

 This is perhaps he&t accounted for by supposing, with Du Hamel, that it is the result of an unnatural graft 

 effected in the bud ; though some think that the shell does always contain the rudiments of two or more 

 kernels, although it rarely happens that more than one is developed. But if two app les or p ears are de- 

 veloped in an incorporated state, which is a case that now and then occurs, 237 

 it is no doubt best accounted for by the graft of Du Hamel. Sometimes 

 the anomaly consists in the figure of the fruit, which is deformed by 

 tumors or excrescences, in consequence of the bite of insects, or injuries 

 of weather producing warts, moles, or specks. Sometimes it consists in 

 the color, producing green melons and white cucumbers. Sometimes it 

 consists in an appendage of leaves, {fig. 237.) 



1586. Habit. Somfe plants, which, when placed in a rich soil, grow to a 

 great height, and affect the habit of a tree, are, when placed in a poor 

 soil, converted into dwarfish shrubs. This may be exemplified'm the case 

 of the box-tree ; and so also in the case of herbaceous plants ; as in that 

 of myosotis, which in dry situations is but short and dwarfish, wliile in 

 moist situations it grows to such a size as to seem to be altogether a dif- 

 ferent plant. The habit of the plant is sometimes totally altered by means 

 of cultivation ; the pyrus sativa, when growing in a wild and uncultivated 

 state, is furnished with strong thorns j but when transferred to a rich and 

 cultivated soil the thorns disappear. This phenomenon, which was ob- 

 served by Linnaeus, was regarded as being equivalent to the taming of ' 

 animals. But this explication is, like some others of the same great 

 botanist, much more plausible than profound, in place of which Professor Wildenow substitutes the fol- 

 lowing, The thorns protruded in the uncultivated state of the plant, are buds rendered abortive from want 

 of nourishment, which when supplied with a sufficiency of nourishment, are converted into leaves and 

 branches. 



1587. Physical virtues. When plants are removed from their native soil and taken 

 into a state of culture, it alters not only their habit but their physical virtues. Thus the 

 sour grape is rendered sweet, the bitter pear pleasant, the dry apricot pulpy, the prickly 

 lettuce smooth, and the acrid celery wholesome. Pot-herbs are also rendered more tender 

 by means of cultivation, and better fitted for the use of man ; and so also are all our fine 

 varieties of fruit. 



1588. Duration. Plants are either annuals, biennials, or perennials, and the species 

 is uniformly of the same class. But it has been found that some plants which are 

 annuals in a cold climate, such as that of Sweden, will become perennials in a hot 

 climate, such as that of the West Indies; this anomaly has been exemplified in tro- 

 paeolum, beet-root, and malva arborica : and, on the contrary, some plants, which are 

 perennials in hot climates, are reduced to annuals when transplanted into a cold climate ; 

 this has been exemplified in mirabilis and ricinus. 



Sect. VI. Of the Sexuality of Vegetables, 



1589. The doctrine that plants are of different sexes, and which constitutes the found- 

 ation of the Linnsean system, though but lately established upon the basis of logical in- 

 duction, is by no means a novel doctrine. It appears to have been entertained even 

 among the original Greeks, from the antiquity of their mode of cultivating figs and palms. 

 Aristotle and Theophrastus maintained the doctrine of the sexuality of vegetables; 

 and Pliny, Dioscorides, and Galen, adopted the division by which plants were then 

 distributed into male and female ; but chiefly upon the erroneous principle of habit or 

 aspect, and without any reference to a distinction absolutely sexual. Pliny seems to 

 admit the distinction of sex in all plants whatever, and quotes the case of a paUn-tree as 

 exhibiting the most striking example. 



1590. Liniueus, reviewing with his usual sagacity the evidence on which the doctrine rested, and perceiv- 

 ing that it was supported by a multiplicity of the most incontrovertible facts, resolved to devote his labors 

 peculiarly to the investigation of the subject, and to prosecute his inquiries throughout the whole extent 

 of the vegetable kingdom ; which great and arduous enterprise he not only undertook, but accomplished 

 with a success equalled to the unexampled industry with which he pursued it. So that by collecting into 

 one body all the evidence of former discovery or experiment, and by adding much that was original of his 

 own, he found himself at length authorised to draw the important contlusion tha* no seed is perfected 



