157 



CXLIV. PORTULACEAE. The Purslane Tribe. 



Pohtplaceje, Juss. Gen. 313. (1789) in part; A. St. Hit. Mem. Plac. Cent. 42. (1815) ; Dt 

 Prodr. 3. 351. (1828); Lindl. Synops. 62. (1829) ; Dec. Mem. de la Soc. d'Hist. Nat. de 

 Paris, {Aug. 1827.) 



Diagnosis. Polypetalous dicotyledons, with unsymmetrical perigynous 

 stamens, concrete carpella, a 1-celled ovarium, herbaceous stems, stamens 

 opposite the petals or twice as many, 2 sepals, and naked seeds with the em- 

 bryo curved round the albumen. 



Anomalies. Sepals 5 in Trianthema and Cypselea. Petals sometimes 

 wanting. 



Essential Character. — Sepals 2, seldom 3 or 5, cohering- by the base. Petals generally 

 5, occasionally 3, 4, or 6, either distinct or cohering in a short tube, sometimes wanting. Sta- 

 mens inserted along with the petals irregularly into the base of tin calyx, variable in number, 

 all fertile, sometimes opposite the petals ; filaments distinct ; anthers versatile, with 2 cells, 

 opening lengthwise. Ovarium superior, 1-celled; style single, or none; stigmata several, 

 much divided. Capsule 1-celled, dehiscing either transversely or by 3 valves, occasionally 

 1-seeded and indehiscent. Seeds numerous, if the fruit is dehiscent; attached to a central 

 placenta ; albumen farinaceous ; embryo curved round the circumference of the albumen, 

 with a long radicle. — Succulent shrubs or herbs. Leaves alternate, seldom opposite, entire, 

 without stipule, or sometimes with membranous ones on each side at the base, flowers axil- 

 lary or terminal, usually ephemeral, expanding only in bright sunshine. 



Affinities. Related in every point of view to Caryophyllese, from which 

 they scarcely differ except in their perigynous stamens, which are opposite the 

 petals when equal to them in number, and two sepals ; the latter character is 

 not, however, very constant. The presence of scarious stipule in several 

 Portulaceae, although perhaps an anomaly in the order, indicates their affinity 

 with Illecebreae, from which the monospermous genera of Portulacese are distin- 

 guished by the want of symmetry in their flowers, and by the stamens being 

 opposite the petals instead of the sepals. So close is the relationship between 

 these orders, that several of the genus Ginginsia in Portulaceae have been referred 

 to Pharnaceum in Caryophylleae, and several Portulaceae have been described 

 by authors as belonging to genera of Illecebreae. Decandolle remarks, that 

 his Ginginsia brevicaulis resembles certain species of Androsace, and that Por- 

 tulaceae have been more than once compared to Primulaceae (Mem. p. 14.) ; 

 and the same author remarks, in another place (Prodr. 3. 351 .), that the genera 

 with indefinite stamens and hairy axillae approach Cacteae, while the apetalous 

 genera tend towards apetalous Ficoideae. 



Geography. A fourth of the order inhabits the Cape of Good Hope, 

 rather more than another fourth is found in South America, 1 only in Guinea, 

 2 in New Holland, 1 in Europe, and the remainder in various parts of the 

 world. They are always found in dry parched places, [except Claytonia and 

 Montia.] 



Properties. Insipidity, want of smell, and a dull green colour, are the 

 usual qualities of this order, of which the only species of any known use are 

 common Purslane and Claytonia perfoliata, which resemble each other in 

 property. 



Examples. Portulaca. Monsia, Talinuni 



