1244 CONTRIBUTIONS FEOM THE NATIONAL HERBARIUM. 



Flowers capitate or in short, very dense spikes. 

 Bracts 4-ranke(i ; heads somewhat elongate, at least in fruit. 



Heads short-pedunculate, the peduncles mostly shorter than the peti- 

 oles 4. L- palmeri. 



Heads long-pedunculate, the peduncles mostly longer than the petioles. 



Leaves mostly 3.5 to 5 cm. long 5. L, graveolens. 



Leaves mostly 1..5 to 3.5 cm. long 6. L. berrlandieri. 



Bracts irregularly imbricate in several ranks. 



Bracts broad, accrescent in fruit, becoming membranaceous and promi- 

 nently veined, the outer ones involucre-like. 



Calyx hirsute with very long straight spreading hairs 7. L. barbata. 



Calsrs hirtellous with short hairs or puberulent or lanate. 

 Peduncles much shorter than the heads. 



Heads in the axils of large leaves 8. L. chrysantha. 



Heads in interrupted, nearly naked spikes or racemes, the floral 



leaves reduced and bractlike 9. L. oaxacana. 



Peduncles longer than the heads, at least in anthesis. 

 Leaves 4.5 cm. long or less, usually obtuse. 



Corolla limb about 8 mm. broad 10. L. formosa. 



Corolla limb about 2 mm. broad 11, L. nutans. 



Leaves mostly 6 to 15 cm. long, usually acute or acuminate. 



Bracts purple 12. L. callicarpaefolia. 



Bracts not colored 13. L. umbellata. 



Bracts not or scarcely accrescent in fruit, not becoming membranaceous 

 and prominently veined. 



Heads commonly 4 or more at each node 14. L. myriocephala. 



Heads usually 1 or 2 at each node. 



Leaves pinnatlfid 15. L. appendiculata. 



Leaves crenate or serrate. 



Leaves linear-oblofig or oblong-lanceolate, 12 mm. wide or less. 

 Heads elongate in fruit ; leaves 2.5 to 6 cm. long. 



16. L. stoecliadifolia. 



Heads not elongate; leaves 1.5 cm. long or less__17. L. fastigiata. 



Leaves oblong-ovate to broadly rhombic-ovate, usually more than 



2 cm. wide. 



Leaves thin, the pubescence all appressed ; peduncles usually much 



longer than the petioles 18. L, dulcis. 



Leaves thick, the pubescence of the lower surface chiefly of spread- 

 ing hairs ; peduncles slightly if at all exceeding the petioles. 



19. L, gerainata. 

 1. Lippia ligustrina (Lag.) Britton, Trans. N. T. Acad. Sci. 9: 181. 1890. 

 Vcrhcna ligustrina Lag. Gen. & Sp. Nov. 18. 1816. 

 Lippia lycioides Steud. Nom. Bot. ed. 2. 2: 254. 1841. 

 Aloysia floribtmda Mart. & Gal. Bull. Acad. Brux. 11: 320. 1844. 

 Sonora to Nuevo Le6n, Puebla, and Zacatecas. Western Texas and southern 

 Arizona. 



Slender shrub, 1 to 4.5 meters high ; leaves subsessile, lance-oblong, 0.5 to 

 2.5 cm. long, acute or obtuse, scaberulous, usually all entire but on young 

 shoots sometimes serrate; spikes racemose; flowers sweet-scented, white or 

 tinged with violet, 4 to 5 mm. long. "Vara dulce " (Neuevo Leon) ; " agrito " 

 (Zacatecas) ; " jaboncillo " (Chihuahua) ; " jazmincillo " (Durango, Coahuila) ; 

 " jasminillo," "vara dulce," " liierba dulce" (Durango); " huele de noche " 



