Lotus

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1981, Flora Europaea. Volume 2. Rosaceae to Umbelliferae, Cambridge University Press : 174

Sect. Lotus . Calyx usually actinomorphic; corolla usually yellow; style not toothed. Legume not inflated. 1-12. L. corniculatus group. Perennial herbs usually with woody stock. Calyx-teeth usually more or less equal, but sometimes curved; corolla 8-18 mm, yellow, sometimes orange or red and yellow. Legume cylindrical, straight. Seeds many. A widespread, variable group containing diploid and tetraploid species. It is sometimes treated as a single species with a number of subspecies and varieties. Recent work has shown that there are a number of relatively local diploid taxa throughout C. & S. Europe and Asia (in addition to 1 and 9), together with more widespread tetraploids. The data available at the present are insufficient to produce a comprehensive account of the group, and it is likely that some of the species recognized here are heterogeneous, while others may not be distinct species.

1 Leaflets of upper leaves linear or linear-lanceolate, at least (3—)4 times as long as wide

2 Calyx-teeth usually shorter than tube; corolla often becoming greenish on drying 1. tenuis 2 Calyx-teeth c. 1| times as long as tube; corolla becoming reddish on drying 2. krylovii 1 Leaflets lanceolate to obovate, usually not more than 3 times as long as wide

3 Calyx-teeth at least 1 | times as long as tube

4Corolla 10-15 mm, about twice as long as calyx 11. presi»

4 Corolla 6-10 mm, not more than 1 | times as long as calyx

12. palustris 3 Calyx-teeth not more than 1 | times as long as tube

5 Stem hollow

6 Leaflets obovate; upper 2 calyx-teeth separated by an acute sinus in bud 9. uliginosus 6 Leaflets rhombic; upper 2 calyx-teeth separated by an obtuse sinus in bud 10. pedunculatus 5Stem solid, sometimes with a narrow hollow at base

7 Calyx-teeth shorter than or almost equalling tube

8 Flowering stems usually more than 10cm; heads mostly

3- to 6-flowered; leaflets 5-15 mm 7. corniculatus 8 Dwarf plants with stout stock and procumbent or ascending flowering stems 2-10 cm; heads 1- to 3(-5)-flowered; leaflets 2-6 mm 8. alpinus 7 At least the lower calyx-teeth equalling or longer than tube

9 Corolla not more than 10(-ll) mm

10 Calyx-teeth all ±straight; calyx and leaves glabrous or subglabrous 5. stenodon 10 Upper and lateral calyx-teeth strongly curved; calyx and leaves pubescent with silvery appressed hairs or with patent hairs 6. glareosus 9 Corolla 10-18 mm

11 Stems procumbent or ascending

12 Calyx ± zygomorphic, the upper and lateral teeth curved 4. delortii 12 Calyx actinomorphic, the teeth all straight

7. corniculatus 11 Stems ± erect

13 Leaflets elliptic-lanceolate 3. borbasii 13 Leaflets elliptic-oblanceolate or obovate 5. stenodon