36 ENGLISH BOTANY. 



Flowers whitish, rose-colour, purple, or yellow, in heads or compact 

 spikes, which are axillary or terminal and generally many-flowered. 



The name of this genus at once expresses its peculiarity, coming from tres, the 

 Latin word for three, and folium, a leaf; all the species having trifoliate or three- 

 parted leaves. The Greeks call it nti<pv\\ov ; the French, trefle ; and the English, trefoil 

 or clover. 



Section I.— TRICOCEPHALUM. Koch. 



Heads axillary, with few fertile flowers, burying themselves 

 in the earth after flowering. Corolla caducous. Calyx without a 

 callous or hairy ring at the mouth of the throat ; fructiferous 

 calyces dilated by the pods, covered by the sterile calyces, which 

 are produced after flowering, and reflexed over the fertile ones 

 so as to look almost like an involucre situated at the apex of the 

 head instead of at its base. Pod sessile, enclosed in the tube of the 

 calyx, 1-seeded. 



SPECIES I— TRIPOLIUM SUBTERRANEUM. Linn. 

 Plate CCCXLVI. 



Annual, pubescent. Leaflets obcordate, nearly entire except 

 at the apex. Stipules adnate for half their length, ovate-acute. 

 Flower-heads stalked. Fertile flowers 2 to 5. Calyx-teeth setaceous, 

 as long as the tube. Corolla longer than the calyx. Upper flowers 

 numerous, barren, produced after the fertile ones, reduced to abor- 

 tive calyces, with the tube filiform, rigid, terminated by 5 points or 

 teeth, reflexed over the fertile calyces around which they form a 

 coma. Fructiferous calyx ovoid, ruptured by the pod, marcescent. 



Among short herbage on pastures in sandy and gravelly places, 

 not unfrequent in the South of England, extending as far North as 

 Lancashire, Nottinghamshire, and Norfolk. 



England. Annual. Early Summer. 



Stems numerous, simple or slightly branched, prostrate, 2 to 18 

 inches long. Leaves on long petioles, digitately trifoliate ; leaflets 

 ^ to f inch long, inversely deltoid, obcordate, finely denticulated 

 at the apical margin. Stipules very large, half-ovate, acute, ad- 

 nate to the petiole for half their length. Peduncles varying in 

 length from 1 to 3 or 4 inches, hooked at the apex in fruit. 

 Fertile flowers generally 2 or 3, subsessile, \ inch long, white 

 tinged with cream-colour, at first erect, afterwards spreading. 

 Flowering calyx with a cylindrical tube and 5 subulate-filiform 



