Trifolium pratense, L.

63. T. pratense L. View in CoL , Sp. Pl. 768 (1753)

(incl. T. borysthenicum Grüner ).

Perennial, caespitose, more or less hairy; stems 5-100 cm. Leaflets obovate, or oblong-lanceolate to nearly orbicular, hairy below, often glabrescent above. Stipules triangular above, abruptly contracted into a setaceous, usually ciliate point; upper stipules very wide. Heads 20-40 mm, globose or ovoid, solitary or paired, usually sessile and involucrate. Calyx-tube 10-veined, usually appressed-hairy; teeth triangular with filiform apex, straight, ciliate, separated by broad sinuses, the lowest one about twice as long as the tube. Corolla 12-15 mm, usually reddish-purple or pink, rarely cream or white, (1—)2 times as long as the lowest calyx-tooth. Legume ovate, with a thickened apex. 2« =14. Meadows and pastures on fertile and moist but well-drained soils from sea-level to 3150 nr, extensively cultivated as a forage crop. Throughout Europe except for parts o f the extreme north and parts o f the extreme south; introduced in Iceland and the Faroes. All except BI Cr Sb. Extremely variable both in the wild and cultivated state in habit, stature, indumentum, size and shape of leaflets and size and colour of flowers. The non-rhizomatous perennial habit, the stipules and the calyx afford the best means of identification. Many ecologically specialized wild populations (for example, of high mountains and coastal habitats) are locally distinct, but it is impossible at present to bring the numerous local taxa into a comprehensive scheme for the whole of Europe. The following indicates some of the variation within the species. Var. pratense . Long-lived perennial. Stems usually 20-40 cm, solid, procumbent or ascending, appressed-hairy, or some rarely with patent hairs above. Heads often solitary. In natural or semi-natural habitats throughout the range of the species. Includes the so-called var. parviflorum Bab. with heads shortly pedunculate, flowers often pedicellate, sometimes bracteate, and corolla not exceeding the calyx, a widely-occurring monstrosity often confused with unrelated species.

Var. sativum Sturm ( T. sativum (Sturm) Crome ). Short-lived perennial. Stems 40-70(-100) cm, hollow, more or less erect, glabrescent or glabrous. Leaflets up to 50 mm or more. Heads large, often paired; corolla usually pink. Includes most of the important cultivars. T. baeticum Boiss. , Voy. Bot. Midi Esp. 2: 726 (1845), from S.W. Spain and Sicilia, is similar but has yellow flowers.

Var. americanum C. O. Harz. Stems with stiff, patent hairs. Leaflets never emarginate, the upper ones lanceolate. Calyx with patent, villous hairs. Corolla deep red. Native in parts of S.E. Europe; introduced into cultivation in C. Europe by way of N. America in 1883, but declining in cultivation since 1910. Often identified with T. expansum Waldst. & Kit. , Pl. Rar. Hung. 3: 237 (1807). Var. maritimum Zabel ( var. villosum Wahlberg ). Stems slender, ascending; hairs dense, patent below, often appressed above. Leaflets and heads relatively small. Corolla pink, white or cream. Maritime pastures and dune-slacks, mainly on the S. coast of the Baltic. Var. frigidum Gaudin. Stems 5-30 cm, stout, procumbent or ascending, densely hairy, at least above. Stipules often hairy over the whole outer surface. Heads large, 30 mm or more wide. Corolla dirty white, often yellowish or pinkish, 1 | times as long as the calyx. 2n= 14. Alps; often treated as a subspecies. Somewhat similar plants from the mountains of E. Portugal, the Pyrenees, Carpathians and the mountains of the Balkan peninsula differ in minor characters, especially flower colour; they are closer to var. pratense in size of heads and indumentum. Other mountain plants of S. Europe have small, relatively few-flowered heads.