SYSTEMATIC BOTANY. 



the sepals do not separate ; but becoming detached 

 at the base, they retain the shape of a hood or 

 extinguisher, till pushed off by the expansion of 

 the corolla. The capsules of the Eschscholtzias 

 are elongated, and are easily known by the large 

 fleshy projection at their base. The plants of the 

 order are easily detected by their general resem- 

 blance to each other, especially in their flowers. 



All the Poppyworts abound in a thick glutinous 

 juice, which poisons by stupefying. All parts of 

 the plant furnish more or less this milky sap, but 

 the main supply is derived from the unripe seed- 

 vessels. When in a green state, those of the large 

 white poppy (P. somniferum) are slightly wounded 

 with a knife, which causes the juice to exude freely ; 

 and on exposure to the air, it concretes or becomes 

 inspissated. In this state, it forms crude or lump 

 opium, which, dissolved in spirit of wine, and 

 filtered, produces the laudanum of the shops. 

 Chemically, opium consists of an insoluble gum, 

 a small quantity of resin, and caoutchouc. Its 

 effects on the animal system depend upon two 

 alkaline principles which it contains namely, 

 morphia and narcotine ; the former producing a 

 sedative, and the latter a stimulating effect. It is 

 curious that the seeds possess none of the stupe- 

 fying properties of the plant, but are mucilaginous 

 and oily, and may be eaten with impunity. The 

 seeds of one species, however (Argemon Mexi- 

 cana), are said to be narcotic, especially when 

 smoked ; but it is probable that in this case the 

 opiate resides in the coating of the seed rather 

 than in the albumen. 



CRUCIFER^E. This is one of the most extensive 

 and important of the natural orders. Most of the 

 genera are herbaceous annuals and perennials. 

 The leaves are alternate, and the flowers are pro- 

 duced in corymbs or racemes, 

 being usually regular, with a calyx 

 of four sepals, and a corolla of 

 four petals, disposed in the form 

 of a Maltese cross : hence the 

 name Crucifera, or cross-bearing. 

 There are six stamens, two much 

 shorter than the others, as shewn 

 under the Linnaean class Tetrady- 

 namia. The pods open naturally 

 when ripe, the valves curling outwards, as in the 

 common cabbage or wallflower, for example. The 

 seeds have no albumen, and the cotyledons are 

 curiously folded down on the radicle. There can 

 be no difficulty in recognising a cruciferous plant 

 when it is in flower, by the cross form of its corolla, 

 as in the preceding figure, and its six stamens, two 

 of which are shorter than the others. 



Among the more common genera may be men- 

 tioned Brasstca, including the cabbage and turnip ; 

 Cheiranthus, the wallflower ; Mathiola, the stocks ; 

 Iberis, the candy-tuft ; Isatis tinctoria, the woad ; 

 Armor acia, the horse-radish ; Sinapis, the mus- 

 tard ; Raphanus, the radish ; and many other well- 

 known plants. The plants are generally distributed, 

 but abound in cold and temperate regions. There 

 are about 1700 known species. 



The properties of the Crucifers are antiscorbutic 

 and pungent, combined with an acrid flavour ; and 

 the seeds of many abound in a fixed oil : properties 

 of which the common cress, mustard, and rape 

 may be taken as examples. Most of them form 

 articles of human food, and are valuable not only 

 for their antiscorbutic properties, but from the 



Crucifer. 



Marsh-mallow. 



fact that they contain a large amount of nitrogen 

 All the cultivated varieties of turnip appear to 

 have been derived from Brassica Rapa. which 

 occurs in a wild state in Britain. 



MALVACEAE. All the plants belonging to this 

 natural order bear a striking resemblance to each 

 other, and have large showy flowers. The petals and 

 sepals are each five in number, but the calyx has 

 three bracts on the outside, having the appearance 

 of a second calyx below the true one. Estivation 

 twisted. The most remarkable part of the flower is 

 the central column, and this is so decided, that a bot- 

 anist is always able to re- 

 cognise one of the Mal- 

 vaceae at first sight. This 

 column is formed by the 

 filaments of the stamens 

 growing together, so as to 

 leave only a small portion 

 just below the anthers 

 free, as is seen in the 

 flower of the marsh-mal- 

 low the lower portion 

 forming a tube round the 

 pistil. The anthers are 

 one-celled, kidney-shaped, and burst transversely, 

 opening inwardly. This peculiar construction of the 

 stamens may be observed distinctly in the mallows, 

 the hollyhocks, and, in short, in all the genera 

 belonging to the order. The styles also grow 

 together, as may be seen when the stamens are 

 removed ; and the carpels, which are of the same 

 number with the styles, form what children call 

 'mallow cheeses.' The carpels are one or many 

 seeded, sometimes closely united, sometimes separ- 

 ated or separable ; fruit capsular or baccate. Most 

 of the species are herbaceous plants ; several, trees 

 or shrubs. Leaves alternate, more or less divided 

 and stipulate, often covered with stellate hairs. 

 The plants abound in tropical regions and in the 

 hotter parts of the temperate zone. 



The economical uses of the order are highly 

 important. Cotton, on which so much of British 

 commerce depends, is obtained from several species 

 of Gossypium, and is the downy hairs which are 

 attached to and envelop the seeds. These hairs, 

 originally of a cylindrical form, at maturity become 

 collapsed into flat bands, and are much twisted. 

 Much confusion exists in botanical works relative 

 to the species of Gossypium, the varying character 

 of the plants having, it is feared, given rise to 

 unnecessary names. The researches of Royle 

 seem to indicate that all the forms known in com- 

 merce should be reduced to four species of plants 

 namely, I. Gossypium herbaceum, which is the 

 common cotton-plant in India, and a variety of 

 which, with buff-coloured hairs, supplies the Nan- 

 kin cotton. 2. G. arboreum, the tree-cotton of 

 India, with red flowers and a fine silky cotton. 

 3. G. Barbadense, Barbadoes cotton, called in 

 India Bourbon cotton, which supplies the highly 

 esteemed Sea Island cotton, as well as the Georgia 

 and New Orleans cottons. 4. G. Peruvianum, 

 Cavanilles (or G. acuminatum), which supplies the 

 Pernambuco or Brazil cotton. The great difference 

 in the value of different kinds of cotton depends 

 chiefly upon the length of staple, precise measure- 

 ments of which have recently been published by 

 the United States government. 



The inner bark of Hibiscus cannabinus furnishes 

 a kind of sun-hemp in India. H. mutabilis has 



