Hylodesmum glutinosum (Muhl. ex Willd.) H. Ohashi & R.R. Mill

Cluster Tick Trefoil

Hylodesmum glutinosum plant

Family - Fabaceae

Stems - To 1m tall, herbaceous, pubescent (sometimes sparse), often glaucous, erect, simple, from a tap root.

Hylodesmum glutinosum stem

Leaves - Alternate, trifoliolate, petiolate, stipulate, mostly grouped near middle of stem below inflorescence and giving a whorled appearance. Stipules 9-12mm long, -2mm broad, lanceolate, acute, pubescent. Petioles to +/-20cm long, pubescent, with an adaxial groove. Lateral leaflets on petiolules to 5mm long. Petiolule thick, pubescent. Leaflets oblique at base, ovate, acuminate, to +12cm long, +6cm broad. Terminal leaflet largest, to 15cm long, +9cm broad, ovate, apex acuminate. Petiolule of terminal leaflet to +5cm long. All leaflets pubescent (sometimes sparsely) above and below, entire, with ciliolate margins, often somewhat scabrous.

Hylodesmum glutinosum leafPressed leaf.

Hylodesmum glutinosum leaves

Inflorescence - Terminal panicles to +40cm long. Axis tomentose. Pedicels to 6mm long in flower, glandular pubescent, often reddish.

Hylodesmum glutinosum inflorescence

Flowers - Papilionaceous. Standard pink, 7mm broad and long, emarginate at apex, glabrous. Keel and wing petals glabrous, pinkish, +6mm long. Stamens monodelphous, 5mm long. Anthers yellow. Style glabrous, white, curved, 2mm long. Ovary 4-5mm long, green, cylindric. Calyx bilabiate, sparse pubescent. Calyx tube to 1mm long. Upper lip shallow, 1-lobed. Lobe to 1.5mm long. Lower lip 3-lobed. Lateral lobes small, acute. Central lobe larger than laterals, acute, 1mm long. Fruit segments typically 3-4, rounded on ventral margin, straight to slightly curved on dorsal surface to +1cm long, +6mm wide, pubescent.

Hylodesmum glutinosum flowerFlower close-up.

Hylodesmum glutinosum calyxCalyx.

Hylodesmum glutinosum fruitsFruits.

Flowering - June - August.

Habitat - Thickets, streambanks, low woods, roadsides, railroads.

Origin - Native to U.S.

Other info. - This is one of the easier species of the Desmodium / Hylodesmum complex to identify because of the leaf arrangement. No other species in these genera has the leaves so obviously bunched in the middle of the stem like a pancake tutu. The fruits are just as "sticky" as the other species and will cling to any fabric.
This species typically grows in shaded, moist locations.

Photographs taken at Alley Spring, Shannon County, MO., 6-27-03.


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