STANDLEY TREES AND SHRUBS OF MEXICO. 1305 



gamopetalous, varying from rotate to funuelform, often bilabiate; stamens 

 usually 4' and didynamous, attached to the corolla tube, the anthers commonly 

 2-celled ; style smple; fruit capsular, many-seeded. 



Numerous genera are represented in Mexico only by herbaceous species. 

 Leaves all alternate. 



Stamens 4; leaves entire 1. LEUCOPHYLLUM. 



Stamens 2 ; leaves crenate 2. GHIESBREGHTIA. 



Leaves all or chiefly opposite. 



Capsule dehiscent by subapical pores. Corolla tubular, red. 



3. GALVEZIA. 

 Capsule dehiscent by valves. 

 Calyx 5-cleft nearly or quite to the base. 



Sterile stamen present, nearly or quite as long as the fertile ones. 



4. PENTSTEMON. 



Sterile stamen none or minute 5. RUSSELIA. 



Calyx tubular or campanulate, the lobes usually shorter than the tube. 

 Pedicels bracteate ; peduncles usually several-flowered. 



Calyx tubular-campanulate, 5-dentate 6. BERENDTIA. 



Calj'x campanulate, 5-lobate 7. HEMICHAENA. 



Pedicels ebracteate, 1-flowered 8. DIPLACUS. 



1. LEUCOPHYLLUM Humb. & Bonpl. PL Aequin. 2: 95. 1809. 



Low shrubs, the pubescence of branched hairs; leaves alternate, entire; 

 pedicels solitary in the leaf axils ; calyx 5-cleft ; corolla funnelform-campanu- 

 late, purple, the 5 lobes rounded, subequal ; stamens 4. 



The species listed are the only ones known. 

 Leaves green, glabrate. 



Corolla lobes glabrous within 1. L. pringlei. 



Corolla lobes villous within 2. L. laevigatum. 



Leaves densely stellate-tomentulose, whitish. 



Corolla rather broadly campanulate, the lobes nearly equaling the tube. 



3. L. texanum. 

 Corolla narrowly campanulate, the lobes one-third to one-half as long as 

 the tube. 



Leaves acute or attentuate at base 4. L. minus. 



Leaves abruptly contracted and usually rounded at base. 



5. L. ambiffuum. 



1. Leucophyllum pring'lei (Greenm. ) Standi. 



Faxonanthus pringlei Greenm. Trees & Shrubs 1: 23. pi. 12. 1905. 



Puebla ; tyiie collected on limestone hills near Tehuacan. 



Shrub, 30 to 60 cm. high ; leaves linear or spatulate-linear, 1.5 cm. long or 

 less, acute or obtuse ; sepals about 8 mm. long ; corolla dark purple, 2 to 2.5 

 cm. long, barbate in the throat. 



2. Leucophyllum. laevigatum. Standi., sp. nov. 



Type collected between Ramos and Inde, Durango {Nelson 4689; U. S. Nat. 

 Herb. no. 332744). 



Young branches densely and finely stellate-tomentose ; leaves oblanceolate- 

 spatulate, 1 to 2 cm. long, 3 to 6 mm. wide, rounded or emarginate at apex, 

 attenuate to a very short petiole, sparsely stellate-puberulent when young but 

 soon glabrous ; sepals linear, 2 to 3 mm. long ; corolla narrowly campanulate, 

 1.5 cm. long, the lobes vlUous-barbate within, nearly as long as the tube ; 

 capsule about 6 mm. long. 



