STANDLEY TREES AND SHRUBS OF MEXICO. 683 



12. MORTONIA. A. Gray, PI. Wright. 1: 35. 18-52. 



Reference: Trolease in A. Gray, Syn. Fl. 1': 400. 1897. 



Low shrub.s ; leaves alternate, persistent, entire, 1-nerved, usually very thick, 

 the margins often revolute ; flowers small, white, cymose, the cymes borne in 

 the upper axils and forming a terminal panicle ; calyx tube 10-angled, 5-lobed ; 

 petals 5, erose-dentate ; stamens 5 ; ovary imperfectly 5-celled ; fruit dry, 

 indehiscent, 1-celled, 1-seeded. 



Leaves suborbicular or oval 1. M. scabrella. 



X,eaves spatulate to linear-oblanceolate. 



Leaves linear-oblanceolate, scarcely broadened toward the apex. 



2. M. palmerL 

 Leaves spatulate or oblanceolate, much broader toward the apex. 



Leaves thin, glabrous, the margins thin, not revolute 3. M. greggii. 



Leaves very thick, the margins strongly thickened, revolute. 



Leaves glabrous 4. M. diffusa. 



Leaves scaberulous on the upper surface 5. M. hidalgensis. 



1. Mortonia scabrella A. Gray, PL Wright. 2: 28. 1853. 



Chihuahua and northern Sonora ; type from San Pedro, Sonora. Southern 

 Arizona to western Texas. 



Shrub, 1.5 to 2.5 meters high, densely branched ; leaves short-petiolate, 5 

 to 9 mm. long, rounded at apex, scaberulous on the upper surface, very thick, 

 with revolute margins ; calyx hirtellous ; petals 2 mm. long ; fruit 4 to 5 mm. 

 long. 



2. Mortonia palmeri Hemsl. Diag. PI. Mex. 24. 1879. 



Coahuila, San Luis Potosi, and Zacatecas; type from the region of San Luis 

 Potosi. 



Branches puberulent ; leaves 1 to 2 cm. long, obtuse or acute, glabrous, very 

 thick, the margins strongly revolute; calyx glabrous; petals suborbicular, 2 

 mm. long; fruit 4 to 5 mm. long. "Afinador " (Zacatecas). 



3. Mortonia gregg'ii A. Gray, PI. Wright, 1: 35. 1852. 

 Mortonia effusa Turcz. Bull. Soc. Nat. Moscou 31*: 453. 

 Coahuila and Nuevo Leon ; type fi'om Rinconada. 



Branches puberulent ; leaves 1.5 to 2.5 cm. long, acute or obtuse, mucronate, 

 bright green ; calyx glabrous ; petals 2 mm. long ; fruit 4 to 5 mm. long. 

 " Afinador " (Coahuila) . 



4. Mortonia diffusa Rose & Standi., sp. nov. 



Puebia; type from Tehuacan {Pringle 8569; U. S. Nat. Herb. No. 461507). 



Shrub, 1 to 1.15 meters high, the branches brown, hirtellous ; leaves short- 

 petiolate, 1 to 1.5 cm. long, obtuse or rounded at apex, mucronate, bright green ; 

 inflorescence comparatively large and lax ; calyx glabrous ; petals suborbicular, 

 2 mm. long. 



Collected also at San Luis Tultilanapa by Purpus (no. 2700). 



5. Mortonia hidalgensis Standi., sp. nov. 



Hidalgo; type from Zimapan {Ehrenherg 1038; U. S. Nat. Herb. no. 617127). 



Branches densely hirtellous ; leaves short-petiolate, 1 to 1.5 cm. long, oblanceo- 

 late or obovate, rounded at apex, mucronate, bright green, glabrous beneath ; 

 inflorescence small and dense ; calyx hirtellous ; petals orbicular, 2 mm. long ; 

 fruit 4 mm. long. 



Collected also at Ixmiquilpan by Rose, Painter, and Rose (no. 9047). 



