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Electronic Flora of South Australia genus Fact Sheet

Family: Leguminosae
Trifolium

Citation: L., Sp. Pl. 764 (1753).

Derivation: Latin name of clover, from tres, three; folium, leaf.

Synonymy: Not Applicable

Common name: Clovers.

Description:
Annual, biennial or perennial herbs, rarely somewhat woody. (not in S.Aust.); leaves usually petiolate, trifoliolate, mostly denticulate; stipules conspicuous, usually entire, adnate to the petiole.

Flowers usually numerous in heads or short racemes, rarely solitary, bracteate or not when heads involucrate; calyx sometimes accrescent, hardened or inflated, throat open or closed by a 2-lipped callosity and a ring of hairs, teeth equal or not; petals narrow, usually united to the staminal tube by their claws, often persistent, purple, red, pink, white or yellow; stamens diadelphous, 9 united by their filaments mostly in their lower half, the tenth facing the standard free, all or 5 of the filaments dilated at the apex.

Pod small, included in the calyx or shortly exserted, often scarious, indehiscent or dehiscent by a ventral suture or by a thickened lid; seeds usually 1 or 2 sometimes up to 10, globose to reniform.

Distribution:  About 300 species, in most of the world except Australia. Extensively cultivated for fodder. (M. Hossain (1961) Notes R. Bot. Gard. Edinb. 23:387-481; Bobrov (1947) The clovers of the U.S.S.R., Acta Inst. Bot. Acad. Sci. URSS ser. 1, 6:164-336; Coombe (1968) Fl. Europaea 2:157; Zohary (1972) Flora Palaestina 2:157-193; Zohary in P. Davis (1969) Flora of Turkey 3:384-448.)

Biology: No text

Key to Species:
8. All heads sessile in leaf axils; flowers sessile; pod enclosed
 
9. Internodes of the stem 1-8 cm; heads distinctly remote; corolla pink, longer than the calyx
T. glomeratum 8.
9. Internodes usually less than 5 mm; heads congested or confluent; corolla white, shorter than the calyx
T. suffocatum 19.
8. At least some heads with a peduncle 5 mm or more; pod enclosed or not
 
10. Leaflets oblong, with glandular teeth; stipules denticulate or fimbriate; peduncles long; pod exserted
T. strictum.
10. Leaflets lacking glandular teeth; stipules broad at the base, membranous, tip sulcate-acuminate; peduncle long or short; pod enclosed
 
11. Peduncle longer than the corresponding leaf; creeping perennials, rooting at the nodes
T. repens 13.
11. Peduncle slender, shorter than the corresponding leaf; annual, not rooting at the nodes
T. cernuum 4.
6. Calyx tube conspicuously inflated, bladdery in fruit (see fig. 353G)
 
12. Creeping perennial, more or less pubescent; peduncle more than 3 cm long; bracts lanceolate, 3-4 mm long, more or less forming an irregular involucre; corolla pale-pink
T. fragiferum 7.
12. Glabrous annual; peduncle less than 3 cm long; bracts scale- like, less than 2 mm long
 
13. Fruiting heads more or less pedunculate; calyx pyriform, pubescent to tomentose; in fruiting stage finally glabrescent, its upper 2 teeth long, evident, divergent
T. resupinatum 14.
13. Fruiting heads more or less sessile; calyx more or less globose, lanate; in fruiting its upper 2 teeth more or less concealed and inconspicuous
T. tomentosum 20.
5. Throat of the calyx usually more or less closed by a ring of hairs or an annular or bilabiate callosity at maturity; flowers ebracteate but heads sometimes involucrate
 
14. Fertile flowers few (2-12) per head, many infertile; inner flowers consisting only of sterile calyces developing after anthesis; peduncle recurved in fruit so that the fruit heads are appressed to the ground
 
15. Corolla whitish or cream, 8-14 mm long, exceeding the calyx for half of its length; mature pods longitudinally netted, as broad as long
T. subterraneum 18.
15. Corolla red to violet (fading to cream and violet when dry),14-18 mm long, 3 or 4 times as long as the calyx; mature pods transversally wrinkled, much broader than long
T. israeliticum.
14. Flowers all fertile, numerous per head; peduncles never recurved
 
16. All or at least some calyces evidently 20-veined, or the 20 veins obscured by dense sericeous hairs; corolla not exceeding the calyx
 
17. Calyx tube glabrous or glabrescent; heads pedunculate, not involucrate
T. lappaceum 9.
17. Calyx tube hairy; heads sessile, with an involucre formed by the 3 upper orbicular stipules
 
18. Heads abscissing in fruit with the stipules and the corresponding leaf; keel short-acuminate, hidden by the wings; corolla pinkish-white, shorter than the calyx
T. cherleri 5.
18. Heads not abscissing but fruiting calyces dehiscent from the axis; keel long-pointed, protruding between the wings; corolla purple, longer than the calyx
T. hirtum.
16. Calyx 10-veined, or some calyces with up to 14 veins; corolla exceeding the calyx or not
 
19. Perennial; heads ovoid, large (2-3 cm wide); corolla pink to reddish-purple, 12-15 mm long, exceeding the calyx.
T. pratense 12.
19. Annuals; heads less than 2 cm wide (except occasionally in T. stellatum in fruit)
 
20. Heads sessile, involucrate
 
21. All leaves alternate
 
22. Throat of the calyx tube open, ciliate; calyx teeth as long as the tube; corolla pink; lateral veins of the leaflets more or less straight, not thickened towards the margin
T. striatum 17.
22. Throat of the calyx tube reduced to a narrow slit by 2 lip-like callosities; the lowest calyx tooth longer than the tube, all spreading in fruit; corolla white, shorter than the calyx; lateral veins of the leaflets recurved, often more or less thickened towards the margin
T. scabrum 15.
21. At least 2 uppermost leaves opposite
 
23. Leaflets 10-20 mm long; calyx tube campanulate, glabrous or sparsely hairy above
T. squamosum.
23. Leaflets 20-70 mm long; calyx tube ovoid, densely hairy
T. squarrosum.
20. Heads pedunculate, without an involucre
 
24. All (including the upper) leaves alternate
 
25. Leaflets of the upper leaves lanceolate, linear-oblong or linear; calyx teeth linear-acuminate or setaceous, plumose; corolla pink
 
26. Leaflets lanceolate, 2-8 cm long; heads 2-10 cm wide, 1 or few, usually terminal; calyx tube as long as the teeth; corolla 10-12 mm long, not or scarcely exceeding the calyx
T. angustifolium 1.
26. Leaflets linear-oblong, 0.5-2 cm long; heads 1-2.5 cm wide, usually numerous; calyx teeth 2 or 3 times longer than the tube; corolla 3-6 mm long, shorter than the calyx
T. arvense 2.
25. Leaflets of upper leaves obovate-cuneate or obcordate; calyx teeth lanceolate or linear; corolla yellowish-white
 
27. Heads capitate, more or less globose in fruit; stipules broad, denticulate; calyx teeth lanceolate, spreading stellately in fruit
T. stellatum 16.
27. Heads spicate, oblong-cylindrical in fruit; stipules entire, scarious, broadened upwards, the free part short; calyx teeth linear-acute
T. incarnatum.
24. At least the 2 uppermost leaves opposite
 
28. Pod slightly exserted from the throat of the calyx tube, visible, not concealed by a ring of hairs in the throat
T. alexandrinum.
28. Pod enclosed in the calyx tube, concealed by the closed bilabiate callosity at the throat
 
29. Leaflets 10-20 mm long; calyx tube campanulate, glabrous or sparsely hairy above
T. squamosum.
29. Leaflets 20-40 mm long; calyx tube ovoid, densely hairy
T. squarrosum.

Author: Not yet available


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