Trifolium incarnatum L.

Crimson Clover


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CW = 5
MOC = 15

© DETenaglia

Family - Fabaceae/Faboideae

Habit - Taprooted annual forb.

Stems - Ascending to erect, to 50 cm, not rooting at the lower nodes, unbranched or few-branched toward the base, densely pubescent with appressed to spreading tawny hairs.

Trifolium_incarnatum_lower_stem.jpg Lower stem.

© DETenaglia

Trifolium_incarnatum_upper_stem.jpg Upper stem.

© DETenaglia

Leaves - Alternate, pinnately trifoliate, long-petiolate toward the stem base to nearly sessile toward the tip, the longest petioles to 60 mm, much longer than the leaflets. Stipules shorter than the associated petiole, broadly ovate to oblong-ovate, fused to above the midpoint and sheathing the stem, the free portions angled at the tips, white to pale green with dark green to reddish purple veins toward the base, the margins toothed toward the tip and rimmed with dark reddish purple or green. Leaflets 10-30 mm long, 10-20 mm wide, all sessile or nearly so, broadly ovate to broadly obovate or nearly circular, broadly angled at the base, broadly and bluntly pointed to rounded or shallowly notched at the tip, the margins irregular or shallowly toothed, the surfaces with relatively long tawny hairs.


© DETenaglia

Inflorescences - Dense narrowly ovoid to more or less cylindric spikes, 20-60 mm long (elongating with age), 10-20 mm wide, the stalk 10-60 mm long. Flowers numerous, sessile or nearly so, ascending at fruiting.


© DETenaglia

Flowers - Calyces 5-10 mm long, the tube 3-5 mm long, moderately to densely long-hairy, the teeth narrowly triangular to nearly linear, 1-2 times as long as the tube, equal or nearly so, long-tapered, plumose, inconspicuously 10-nerved. Corollas papilionaceous, 10-17 mm long, longer than the calyx lobes, red to dark red, the banner outcurved, linear-oblong to narrowly elliptic, usually sharply pointed at the tip, finely and relatively faintly nerved.

Trifolium_incarnatum_flowers.jpg Flowers close-up.

© DETenaglia

Fruits - Legumes 3-4 mm long, oblong-ovoid, sessile, the outer wall papery, 1-seeded. Seeds 1.9-2.3 mm long, ovoid to elliptic-ovoid, tan to brown.

Flowering - April - July.

Habitat - Fields, pastures, open disturbed areas.

Origin - Native to Europe.

Lookalikes - None.

Other info. - This striking species of clover occurs sporadically, in a few widely scattered counties of Missouri, usually associated with deliberate planting. It is easily identified by its silky-hairy stems and cylindrical racemes of brilliant red flowers.

Crimson clover, also known as Italian clover and several other names, has a long history of cultivation in Europe. It was introduced to the U.S. in 1818 for use as cattle fodder and nitrogen-fixing green manure. Missouri's plants have been called var. incarnatum, which is defined by red corollas. Southern European plants with lighter colored corollas have been called var. molineri.

Photographs taken somewhere in NC., 4-20-03 (DETenaglia).