190 BOTANY. 



eleven genera and fifty-three species. All the species yield mucilage in 

 large quantity, and none are poisonous. The Hollyhock, Althcea rosea, is 

 an ornamental plant, as are many other species. The Sun-hemp of India 

 is derived from Hibiscus esculentus. Okra, a substance much used in 

 soups, is the fruit of Abelmoschus esculentus. Various species of Gossypium 

 furnish cotton, which consists of the hairs surrounding the seed. These, 

 when dry, exhibit to the microscope a peculiar twisted appearance, by 

 which they are readily recognised. The Sea Island, New Orleans, and 

 Georgia cottons, considered the best, are obtained from G. barbadense. G. 

 acuminatum furnishes the South American cotton ; G. arboreum, the Indian 

 tree cotton ; G. nanking, nankeen cotton. The nankeen color is said to be 

 imparted by the fruit of Acacia arabica. 



Gossypium herbaceum. Cotton plant {pi. 67, ßg. 11); a, a flowering 

 branch, and a (to the right hand), a flower ; h, capsule with the calyx ; c, 

 capsule ; d, germs ; e, cross-section of the capsules ; /, seeds with the cotton 

 hairs ; g^n, seeds with the embryo. 



Order 197. Vivianiaceje, the Yiviania Family. Sepals five, united. 

 Petals five, hypogynous, unguiculate, persistent, with twisted aestivation. 

 Stamens ten, hypogynous ; filaments free ; anthers bilocular, opening 

 longitudinally. Ovary free, three-celled ; stigmas three. Capsule three- 

 celled, three-valved, loculicidal ; seeds, two in each cell, with a curved 

 embryo lying in fleshy albumen. Herbaceous or suflfruticose plants, with 

 opposite or verticillatc exstipulate leaves. Natives of South America, 

 r having no properties of im2)ortance. Genera four, species fifteen . 

 Examples : Viviania, Caesarea. 



Order 198. CARYOPHYLLACEiE, the Chickweed Family. Sepals four or 

 five, free, or united in a tube, persistent. Petals four to five, hypogynous, 

 unguiculate, often bifid or bipartite, occasionally 0. Stamens usually 

 double the number of the petals, or, if equal, usually alternate with them ; 

 filaments subulate, sometimes united ; anthers innate, bilocular, dehiscence 

 longitudinal. Ovary single, often stalked or supported on a gynophore 

 composed of two to five carpels, M-hich are usually united by their edges, 

 but sometimes the edges are turned inwards, so as to form partial 

 dissepiments; stigmas two to five, with papillae on their inner surface. 

 Capsule unilocular, or imperfectly bi-quinquelocular, two- to five-valved, 

 opening either by valves, or more commonly by twice as many teeth as 

 stigmas ; placenta in the axis of the fruit. Seeds usually 00, amphitropal, 

 with mealy albumen, and a peripherical embryo. Herbs, sometimes 

 sufiiTiticose plants, with opposite, entire, exstipulate, sometimes connate 

 leaves, and usually cymose inflorescence. They inhabit chiefly temperate 

 and cold regions. Lindley mentions 53 genera and 1055 species, of which 

 11 genera and upwards of 100 species belong to the United States. 



Sub-order 1. Alsinew. Sepals nearly or quite distinct. Petals sessile. 

 Examples : *Mollugo, * Arenaria, *Stellaria, *Cerastium. 



Sab-07'dsr 2. Silenem. Sepals united into a cylindrical tube. Petals 

 unguiculate. Examples : *Silene, *Lychnis, *Saponaria, *Dianthus. 



Some authors separate a third sub-order, Molugineae, from Alsineae, with 

 190 



