1 12 OXALIDACE.E. 



versely rugose inner integument, and elastically recurved. 

 Embryo straight or nearly so, about the length of the thin 

 and fleshy albumen : cotyledons oval, flat, foliaceous : rad- 

 icle superior. 



Herbs low and often acaulescent, with a sour watery juice, 

 and alternate commonly digitately trifoliolate leaves on slen- 

 der petioles, circinate in vernation ; the leaflets almost always 

 obcordate or two-lobed. Stipules rarely present. Pedun- 

 cles umbellately or cymosely few - many-flowered. Foliage 

 sometimes sensitive, usually drooping or closing at nightfall. 



Etymology. The name is derived from 6^vs, sour, from their acid taste. 



Geographical Distribution. This large genus is widely distributed 

 over the world, but far the greater part are natives of Tropical America and 

 of the Cape of Good Hope. A few species belong to the northern temper- 

 ate zone : there are none in the frigid zone. 



Properties. These are detailed in the account of the order. 



PLATE 144. OxALis violacea, Linn.; — of the natural size, with the 

 bulb as in summer, producing numerous subterranean branches, 

 and a thickened root below : on the left an earlier state of the bulb 

 is represented. 



1. Diagram of the flower. 



2. Pistil, with the ring of stamens laid open ; magnified. 



3. A magnified sepal, with its glandular tip ; outside view. 



4. A magnified stamen ; inside view. 



5. Vertical section of a pistil, magnified. 



6. An ovule, more magnified. 



7-11. OxALis stricta, Linn. ; — the fruit and seed. 



7. Dehiscent capsule, enlarged. 



8. A seed (inverted), more magnified. 



9. The same, with the arilliform testa spontaneously separated. 



10. Transverse section of the same, with the testa just separating. 



11. Embryo detached and more magnified. 



