TROPiEOLACE^ — PITTOSPOEACB^. 465 



the place of leaves. The genus Hugonia'is placed by some in the order 

 Linacese, along with Koucheria. There are about 6 known genera, and 

 upwards of 230 species. Examples — Oxalis, Averrhoa, Hugonia. 



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 l?e 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. sen- 

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

 to their closing and opening by Morren (p. 377). Oxalis crenata, 

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

 tute for potatoes. The acid fruits of Averrhoa Bilimhi and Carambola 

 are used in the East Indies as food. 



Order 49. — Tkop^olace*, the Indian Cress Family. (Polypet. 

 Hypog.) Sepals usually 5, the upper spurred (fig. 299, p. 198) ; 

 aestivation slightly imbricate. Petals often 5, hypogynous, more or 

 less unequal, sometimes abortive (fig. ^41, p. 366) ; aestivation con- 

 volute. 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 pen- 

 dulous. Fruit indehiscent, usually composed of 3 pieces. Seeds 

 exalbuminous, with a large embryo, which has thick, often united, 

 cotyledons, and a radicle next the hilum. — Herbaceous trailing or 

 twining plants, having a delicate texture, with alternate exstipulate 

 leaves, and axillary, often gay, flowers. They are natives of the tem- 

 perate parts of America, and are extensively cultivated on account of 

 their showy yellow, orange, scarlet, and occasionally blue flowers. 

 The free spur of Tropseolum represents the adherent spur of Pelar- 

 gonium. They have more or less pungency in their fruit, which is 

 used as a cress. The unripe fruit of Tropceolum majus, common In- 

 dian Cress, or Garden Nasturtium, has been pickled, and used as capers. 

 LiMNANTHACB^ are included by some in this order. They are charac- 

 terised by regular flowers, valvate sepals, glands alternating with the 

 petals, stamens double the number of the petals, carpels not beaked, 

 indehiscent, separating from the axis, ovules solitary, with an inferior 

 micropyle. The species are found in North America. Limnanthes 

 is a Oalifornian genus, with showy flowers. Their roots are sometimes 

 eaten. Genera 4, including 40 species. Example, Tropseolum, Flcer- 

 kea, Limnanthes. 



Order 50. — PiTTOSPORACEiE, the Pittosporum Family. (Polypet, 

 Hypog.) Sepals 4 or 5, deciduous ; distinct or partially united ; aesti- 

 vation imbricated. Petals 4 or 5, sometimes slightly cohering, with 



2 H 



