SYSTEMATIC BOTANY. 



ANGIOSPERM^E. 



CHENOPODIACE^E. Chiefly herbs with herba- 

 ceous (greenish) flowers. The embryo is coiled 

 round mealy albumen, or spiral without albumen ; 

 ovary, free, one-celled ; stamens, inserted into the 

 base of the perianth. Many of the species are 

 used as pot-herbs, such as Spinach, Orach, and 

 English mercury (Chenopodium Bonus-Henricus). 

 The seeds of C. Quinoa are used as food. The 

 Beet (Beta vulgaris) yields a large proportion 

 of sugar, and in the form of mangold-wurzcl is an 

 important forage plant throughout Europe. 



LAURACE/E. An important order, comprising 

 about 450 species. They are tropical trees, with 

 elegant foliage and aromatic properties, having 

 exstipulate, alternate (seldom opposite) leaves, 

 with inconspicuous flowers. The perianth is from 

 four to six cleft, the limb sometimes obsolete ; 

 estivation, imbricate. The male and female 

 flowers are distinct : the former have four, six, or 

 eight stamens, opposite the segments of the peri- 

 anth ; the latter have four or more abortive sta- 

 mens, furnished with glands, but without anthers, 

 a one-celled, one-seeded ovary, with a simple 

 style and an obtuse-crested stigma. The fruit is 

 fleshy and indehiscent, naked, or covered by the 

 enlarged and fleshy perianth. The two or four 

 celled anthers, with the valves curling upwards 

 when ripe, and the filaments furnished with kid- 

 ney-shaped glands at their base, are character- 

 istics of the order. 



The chief genera are Laurus, the sweet bay ; 

 Sassafras, the sassafras-tree ; Persea, the avocado- 

 pear ; Camphora, the camphor-tree ; Cinnamo- 

 mum, the cinnamon-tree ; Cassytha, the Dodder- 

 laurel ; Tretranthera, and Cryptocarya. The true 

 laurels have two anthers, and naked fruit ; the 

 cassia, cinnamon, and camphor have four anthers, 

 and the fruit covered. The plants contain essen- 

 tial oil in abundance, which imparts to them a 

 peculiar sweet, though strong penetrating odour, 

 and a warm and pleasant taste ; hence they yield 

 some of our most grateful stimulants and spices. 

 Cinnamon, cassia, camphor, benzoin, and sassa- 

 fras are products of the family ; the roots of the 

 sweet bay yield a violet dye ; and a concrete oil, 

 used in candle-manufacture, is obtained from 

 the fruit of Laurus glauca. The branches of 

 Laurus nobilis, or sweet bay, were used to crown 

 the victors in the ancient games. This plant 

 seems to be the ezrach of the Bible, translated 

 ' green bay-tree.' 



ARISTOLOCHIACE^G. There are only six or 

 eight genera in this order, the members of which 

 are herbaceous plants or shrubs, of climbing 

 habit. The characters are flowers, hermaphro- 

 dite ; perianth, tubular, adherent with the ovary, 

 and divided into three segments ; stamens, from 

 six to twelve epigynous, sometimes free and dis- 

 tinct, in other cases adhering with the style and 

 stigma ; ovary, three to six celled ; style, short ; 

 stigma, six-rayed ; fruit, capsular, dry, or succu- 

 lent, three to six celled, and many-seeded ; seeds, 

 thin, flat, and of a dark-brown colour. 



The chief genera are Aristolochta, the birth- 

 wort ; and Asarum, the wild-ginger of North 

 America. Many of the species are natives of 

 Europe ; but they abound in the tropical regions 

 of South America; Art's f. Clematitis (common birth- 



wort) and Asar. Eitropatum (Asarabacca) are the 

 only two found in Britain, and are doubtfully 

 native. 

 The birthworts arc heating and stimulating in 



Aristolochia. 



their properties, and act chiefly on the skin and 

 kidneys. The prepared root of Arist. scrpentaria 

 (Virginian snake-root) is used in ague, typhus 

 fever, and in gout being one of the ingredients of 

 the celebrated Portland powder. The snake-root 

 is regarded as an antidote against serpent-bites. 

 A drop or two of the juice, if introduced into the 

 mouth of one of these reptiles, has the power of 

 stupefying it, so that it can be handled with 

 impunity ; and a few drops swallowed almost 

 instantly cause death. The roots of the species 

 of Asarum have bitter and acrid properties, and 

 a disagreeable odour like that of the stapelias. 

 Asarum canadense has an aromatic flavour, and 

 is often used by the country-people in lieu of the 

 true ginger. 



EUPHORBIACE^E. In Britain, this order is 

 represented by the small weedy spurges of our 

 gardens and waste grounds, but exhibits a nobler 

 aspect in hot regions, where the tall cacti-like 

 columnar species attain gigantic proportions. 

 The juice is usually acrid and milky, and the 

 fruit formed of three globose carpels in union. 

 The purgative resin Euphorbium is supplied by 

 E. offidnarum and other species. Hura crepitans 

 is the sand-box tree, whose fruit bursts with a 

 loud noise. Ricinus communis yields castor-oil. 

 The vegetable tallow of China is derived from 

 Stillingia sebifera. The seeds are beaten down 

 and boiled to separate the tallow, which fuses at 

 80, and is used for candles. Aleurites triloba 

 yields Eboe-oil, used by artists. Croton Tiglium 

 seeds yield croton-oiL Janipha manihot is the 

 cassava or manioc plant of the West Indies. 

 Jatropha Curcas produces the physic-nut. Old- 

 fieldia Africana is the tree which supplies the 

 African teak or oak. 



URTICACEJE ARTOCARPACE.E. These are ex- 

 tensive orders of plants, which, to the uninitiated, 

 may appear very dissimilar as illustrated, for 

 example, by the common nettle, the hop, the 

 hemp, the pellitory of the wall, the bread-fruit tree, 

 the cow-tree, upas, mulberry, common fig, banyan, 

 and India-rubber tree, all of which, though ex- 

 hibiting different habits and products, are not 

 only strikingly alike in their essential characters, 



105 



