86 WILLIAM TRELEASE ON THE 



adapted to i^ollination by these insects. Darwin^ has shown that the flowers are fertile 

 with tlieir own pollen. Floerhea and, apparently, Limnanthes Macoumi, with smaller, 

 inconspicuous flowers, are apj^ai-entl}" adapted to pollination by small bees and are likely 

 to be found fully self-fertile, but no ol)servations have been made on them. The seeds 

 of both genera are enclosed in integuments consisting of lirown, rather thin-walled 

 cells, the outer and inner layers of which arc collapsed and closely surrounded by the 

 indehiscent, rugose-tuberculate pericarp, which is soft, and consists externally of thick- 

 walled, rather pale cells, some of which, on the outside, develop into thick-walled, ver- 

 i-ucose, rounded papillae. I am unable to offer any suggestion concerning their dissem- 

 ination, or the use of the peculiar roughening of the pericarji. (]N'ote 8.) 



OXjVLIDEAE. 



Flowers regulai', 5-merous, homogone or hetei'ogone; sepals imbricate, persistent; 

 petals convolute, distinct or somewhat united near the base, deciduous; stamens twice 

 as many as the sepals, sometimes with an additional set of auricles or sterile scales; 

 glands greatly reduced or wanting, alternate with the sepals when present; carpels 

 alternate with the sepals. Oxalideae of continental writers. — Five genera, three of them 

 confined to tropical Asia, one South American, the other widely distributed. 



OXALIS, L. Gen. n., 382 ; Benth. and Hook. Gen., i, 276, 



Annual or perennial often bulbiferous herbs, sometimes suffrnticose or frutescent, 

 with compound petiolate mostly estipulate leaves; stamens ten, monadelphous below, 

 in two sets of different length, all antheriferous ; ovary somewhat lobed, forming a 

 loculicidal capsule tipped by the persistent distinct styles; seed with a longitudinally- 

 dehiscent arilloid outer coat, the firm more or less viscid inner integument usually 

 sculptured; embryo straight, with plane cotyledons, in abundant albumen. Oxys of 

 older writers. — About 220 species, mainly in South America and Africa. 



Synopsis of Xorth American Species. 



*Caulescent ; flowers yellow, sometimes, like the rest of the plant, tinged with red-pur- 

 ple. 



Leaves unifoliolate, with free setaceous stipules ... 0. dicliondraefolia. 



Leaves pinnately trifoliolate, estipulate ..... O. Berlandierl. 



Leaves palmately trifoliolate, estipulate or with short adnate stipules; leaflets subses- 

 sile, more or less obliquely obcordate-cuneate. 

 Leafy branches from a stout Avoody caudex 0. Wrightii. 



' Cross and Sell'-ferlilizatioii, Index. 



