Desmodium Leguminosae 605 



Stems glabrous or nearly so 10. D. paniculatum. 



Stems covered more or less densely with short, hooked hairs or with 

 long, spreading hairs in addition to any short, hooked hairs that 



may be present 10a. />. paniculatum var. pubens. 



Leaflets of an ovate type. 

 Leaflets glabrous and glaucous beneath; stems glabrous; inflorescence 

 more or less puberulent; lower petioles mostly 4-8 cm long; seg- 

 ments of loment generally 4-6, usually about 8 mm long, of a 



rhomboidal type 11. D. laevigatitm. 



Leaflets not glaucous and more or less pubescent to velvety beneath; 

 stems usually more or less villous, rarely somewhat glabrate. 

 Petioles of median leaves more than one and a half times as long as 

 the petiolule of the terminal leaflet, generally about twice as 

 long; leaflets more or less pubescent beneath but not velvety to 

 the touch; stipules narrow-lanceolate, from a dilated base, long- 

 acuminate, early deciduous; segments of loment of a rhomboidal 



type, very rarely of an oval type 12. D. Dillenii. 



Petioles of median leaves less than one and a half times as long as 

 the petiolule of the terminal leaflet, generally about as long or 

 shorter; leaflets velvety pubescent beneath, usually conspicuously 

 thicker and more obtuse at the apex; stipules ovate-lanceolate, 

 acuminate, pilose and ciliate, brick red; segments of loment of 



an oval type, generally strongly rounded below 



13. D. viridiflorum. 



Stipe of loment shorter than the calyx; segments of loment 1-5, rounded on 

 the ventral side. 

 Leaflets glabrous above, glabrous beneath or with a few hairs on the 

 principal veins, the terminal one very obtuse, ovate to narrow-ovate 



or oval, 15-30 mm long 14. D. marilandicum. 



Leaflets more or less pubescent both above and beneath. 



Terminal leaflet a little longer than wide, mostly 20-30 mm long, ovate 



to oval 15. D. ciliare. 



Terminal leaflet usually twice as long as wide or longer, mostly 20-60 

 (75) mm long, oblong-ovate to ovate-lanceolate. 

 Calyx usually 4-5 mm long, the midnerve of the lobes prominently 

 purple; segments predominantly more than 3; plants usually of 



moist habitats 9- D. canadense. 



Calyx usually 2-3 mm long, the midnerve not prominently purple; 

 segments fewer than 3; plants usually of dry, infertile or dry, 

 sandy places 16. D. rigidum. 



1. Desmodium rotundifdlium (Michx.) DC. (Meibomia Michauxvi 

 Vail.) Prostrate Tickclover. Map 1236. Infrequent, but probably found 

 in all the counties of the state in which there are sandy or clayey black 

 oak and chestnut oak ridges. Rare in all parts except in the unglaciated 

 region where it becomes more or less frequent. Probably absent from 

 some of the counties of the central part 'whose soil is a black loam and 

 where black oak is absent. 



Eastern Mass. to Minn., southw. to Fla. and La. 



2. Desmodium sessilifolium (Torr.) T. & G. {Meibomia sessilifolia 

 (Torr.) Ktze.) Sessile-leaf Tickclover. Map 1237. Infrequent in the 

 northern and western counties in very dry, sandy or gravelly soil in prairie 

 habitats or in open woodlands that have recently been prairies. 



Mass. to Ont. and Mich., southw. to Conn., Miss., and Tex. 



