Trigonella,] XXV. PAPILIONACEiE. 109 



Europe, extending northward to Denmark. In several maritime counties 

 of England, Ireland, and southern Scotland. Fl. early summer. 



VIII. TRIFOLIUM. CLOVER 



Herbs, with stipules adhering to the leafstalks. Leaves pinnately or 

 almost digitately trifoliolate ; the leaflets often toothed. Flowers red, 

 white or yellow, in close heads. Calyx 5-toothed. Petals narrow, often 

 connected together, and attached to the staminal tube by the claws, and 

 usually remaining round the pod after fading. Stamens diadelphous, 

 the upper one entirely free. Pod enclosed in the calyx, or in the per- 

 sistent petals, containing from 1 to 4 seeds, and usually indehiscent. 



A very widely spread and numerous genus in the northern hemisphere, 

 both in the New and the Old World, deficient in several tropical regions, 

 but reappearing in southern America and Africa. It is readily dis- 

 tinguished from Medicago and Trigonella by the pod, from Melilotus by 

 the compact heads of flower, and most of the species differ from all 

 allied genera by the petals, either all or the three lower ones only, 

 connected by their claws with the staminal tube. 



C Heads of flowers pedunculate in the axils of the leaves, or above the last 

 1 J leaves of the stem 2 



| Heads of flowers closely sessile in the axils, or within the last leaves of the 



V stem 15 



2 /Flowers yellow, reflexed and brown when faded 3 



\ Mowers red, white, or cream-coloured 5 



( Flowers 30 to 40, in a compact head. Standard distinctly furrowed when 

 3-{ faded 19. I 7 , procumbens. 



( Flowers not more than 20 in the head. Standard scarcely striate . . .4 



/"Flowers usually 10 to 20 in the head, sessile or on very short pedicels. 

 .1 Central leaflet usually raised above the others . .' . 20. T. minus 



j Flowers 2 or 3, rarely 5 or 6 in the head. Pedicels as long as the calyx- 



^ tube. Central leaflet usually sessile between the others . 21. T. filiforme, 

 5 /Flowers pedicellate in the head, reflexed after fading fl 



\ Flowers sessile, erect 7 



( Stem creeping and rooting at the nodes 17. T.repens. 



6 ■< Stem ascending or erect and branched, without roots at the nodes. 



( 18. T. hybridum. 



y, / Stem creeping and rooting at the nodes, or closely prostrate .... 8 



\ Stem ascending or erect 9 



(Heads globular. Flowers small. Calyx much inflated after flowering. 

 8 ) 16. T. fragiferum. 



y Heads of few rather large flowers. Peduncles turned down into the ground 



( after flowering 15. T. subterraneum. 



q( Heads oblong or cylindrical when fully out 10 



\ Heads ovoid or globular • . . . .11 



10 j Corolla small, shorter than the long, fine calyx-teeth . . 2. T. arvense. 



( Corolla showy. Standard longer than the calyx-teeth . 1. T. incarnatum. 

 . .. / Corolla small, 1 to 3 lines long 12 



\ Corolla showy, 5 to 6 lines long or more . 13 



/ Calyx-teeth short, lanceolate, slightly ciliate ... 7. T. maritimum. 



| Calyx-teeth short, subulate, glabrous 11. T. striatum, 



12 < Calyx softly hairy, the teeth longer than the corolla spreading after flower- 



j ing 3. T. stellatum. 



\ Calyx inflated after flowering. Standard turned outwards 14. T. resupinatum. 

 jof Annual. Teeth of the calyx nearly equal . . . 1. T. incarnatum. 



\ Perennials. Lower tooth of the calyx longer than the others . . . .14 

 14 j Flowers red 6. T. medium, 



I Flowers cream-coloured 4. T. ochroleucum. 



ic /Corolla showy, 6 lines long or more 16 



\ Corolla small, 1 to 3 lines 17 



