OXALIDACE^E TROP^EOLACE-S!. 387 



in the cells, and they then curl up in a peculiar manner (^[ 27, 606). 

 They have usually showy flowers, but their properties are unimportant. 

 Lindley mentions 3 genera, including 110 species. Examples Im- 

 patiens, Hydrocera. 



820. Order 51. Oxalidacetc, the "Wood-sorrel Family. (Polypet. 

 Hypog.) Sepals 5, equal, sometimes cohering slightly at the base, 

 persistent, imbricate in aestivation. Petals 5, equal, unguiculate, 

 hypogynous, with a twisted aestivation. Stamens 10, more or less 

 monadelphous, in 2 rows; those opposite the petals being longer than 

 those in the outer row; anthers erect, bilocular. Ovary usually quin- 

 quelocular; styles filiform, distinct; stigmas capitate or slightly bifid. 

 Fruit capsular, membranous or fleshy, usually 5 -celled, and when 

 dehiscent 5-10 valved. Seeds few, anatropal, albuminous, attached 

 to a central placenta, sometimes with a peculiar elastic integument; 

 embryo straight, as long as the fleshy albumen, with a long radicle and 

 leafy cotyledons. Herbs, undershrubs, or trees, with alternate, rarely 

 opposite compound (occasionally simple) leaves, which are generally 

 without stipules. They are found in the hot as well as the temperate 

 parts of the world, and are abundant in North America and at the 

 Cape of Good Hope. In some cases phyllodia, or winged petioles, 

 occupy the place of leaves. There are about 6 known genera, and 

 upwards of 320 species. Examples Oxalis, Averrhoa, Hugonia. 



821. They are often acid in their properties. Some of them yield 

 esculent roots. Oxalis Acetosella, common Wood-sorrel, receives its 

 name from its acid taste. It contains binoxalate of potash, which is 

 sometimes called the salt of sorrel, and at other times the essential salt 

 of lemons. The plant has been used as a refrigerant and antiscorbutic. 

 Its leaves are trifoliate, and some have considered it to be the true 

 Shamrock, in consequence of being in flower about the period of the 

 year when St. Patrick's day occurs. Some of the oxalises, as 0. sensi- 

 tiva, have sensitive leaves, and experiments have been made in regard 

 to their closing and opening by Morren (^[ 660). Oxalis crenata, 

 esculenta, and Deppei, yield tubers, which have been used as a substi- 

 tute for potatoes. The acid fruit of Averrhoa Bilimbi and Carambola is 

 used in the East Indies as food. 



822. Order 52. Tropseolaceie, the Indian Cress Family. (Polypet. 

 Hypog.) Sepals usually five, the upper spurred (fig. 275); aestivation 

 slightly imbricate. Petals often 5, hypogynous, more or less unequal, 

 sometimes abortive (fig. 542); asstivation convolute. Stamens 8 or 10, 

 seldom fewer, free, almost perigynous ; anthers bilocular, innate. Ovary 

 triquetrous, composed of 3-5 carpels, with a single style, and 3-5 

 acute stigmas; ovules solitary, often pendulous. Fruit indehiscent, 

 usually composed of 3 pieces. Seeds exalbuminous, with a large em- 

 bryo, which has thick, often united, cotyledons, and a radicle next the 

 hilum. Herbaceous trailing or twining plants, having a delicate tex- 



