146 NEW YORK STATE MUSEUM 



Waste places, fields and roadsides, Massachusetts to southern New 

 York, Maryland and Missouri. Adventive or naturalized from Europe. 

 Flowering from June to August. 



THE TICK TREFOILS 



M e i 1.) m i a 



The Tick Trefoils are all perennial herbs, often with stout roots, erect, 

 ascending or trailing stems and three-foliolate leaves. The flowers are 

 usually rather small, ptirplish in terminal or axillary, compound or simple 

 racemes or panicles. Calyx two-lipped, the upper lip two-toothed, the 

 lower lip with three acute or attenuate teeth. Stamens monadelphous 

 or diadelphous (nine and one) ; anthers all alike. Fruit (loment) flat, sessile 

 or stalked with several joints which are easily separable at maturity. 



A large genus of plants with about sixteen representatives in New 

 York State. The following key is given as an aid in placing the various 

 species not fully described and illustrated here. 



Loment not constricted above, deeply constricted below, long-stalked; leaflets broad 

 Panicle terminal on the leaf}' stem 



Leaves crowded at the base of the jjanicle M. g r a n d i f 1 o r a 



Leaves scattered along the stem M. p a u c i f 1 o r a 



Panicle arising from the base of the plant, its stalk usually leafless 



M. n u d i f 1 o r a 

 Loment constricted on both margins, more deeply below than above 

 Stems trailing or reclining 



Leaflets orbicular, i to 2 inches long and pubescent M. m i c h a u x i i 



Leaflets ovate or oval, dull green M. glabella 



Stems erect or ascending 



Leaves sessile or nearly so; leaflets linear or lanceolate M. s e s s i 1 i f o 1 i a 



Leaves petioled 



Joints of the loment notably longer than broad 



Leaflets obtuse, yellowish green, rough-pubescent. . . . M. canescens 



Leaflets long-acuminate M. b r a c t e o s a 



Joints of the loment little longer than broad 

 Loment distinctly long-stalked in the calyx 



