WOOTON AND STANDLEY FLOEA OF NEW MEXICO. 607 



4. HOUSTONIA L. Bluets. 



Annual or perennial herbs, sometimes woody at the base or throughout, 30 cm. high 

 or less; leaves opiJosite, entire, often cilia te, mostly naiTow; flowers perfect, often 

 dimorphous, solitary or cymose; hypanthium subglobose or obovoid; sepals 4; corolla 

 white or blue or bright rose pink, narrowly funnelform or salverform; stamens 4; 

 ovary 2-celled, the styles united to the narrow stigmas; capsules partly inferior, more 

 or less distinctly 2-lobed; seeds few or several in each cell. 



KEY TO THE SPECIES. 



Annual 1. H. humifusa. 



Perennials. 



Leaves fasciculate; stems woody throughout 2. H. fasciculata. 



Leaves opposite; plants woody only near the base, if at all. 



Corolla tube 2 cm. long; plants 6 cm. high or less 5. //. rubra. 



Corolla tube less than 1 cm. long; plants more than 6 cm. 

 high. 



Pedicels re flexed after an thesis 6. H. urightii. 



Pedicels erect. 



Stems glabrous, herbaceous; leaves soft, not 



acerose- tipped 4. H. rigidiuscula. 



Stems puberulent, woody below, leaves rigid, 



acerose-tipped 3. IF. polypremoidcs. 



1. Houstonia humifusa A. Gray, Proc. Amer. Acad. 4: 314. 1859. 

 Eedyotis humifusa A. Gray, Bost. Joum. Nat. Hist. 6: 216. 1850. 



Type locality: "Open gravelly banks of streamlets, near Fredericksburg," Texas. 



Range: Western Texas to eastern New Mexico. 



New Mexico: Twenty miles south of Roswell (Earle 278). 



2. Houstonia fasciculata A. Gray, Proc. Amer. Acad. 17: 203. 1882. 

 Type locality: "Southwestern borders of Texas, at Presidio." 

 Range: Western Texas and southern New Mexico; also in Mexico. 

 New Mexico: Organ Mountains (Vasey). LTpper Sonoran Zone. 



3. Houstonia polypremoides A. Gray, Proc. Amer. Acad. 21: 379. 1886. 

 Type locality: Santa Eulalia ]\lountaius, near Chihuahua, Mexico. 

 Range: Southern New Mexico and western Texas to Mexico. 



New Mexico: Clayton; Bishops Cap; ^Miite Mountains; Queen; Gray; Buchanan; 

 Lakewood; Torrance. Lower and Upper Sonoran zones. 



4. Houstonia rigidiuscvila (A. Gray) Woot. & Standi. Contr. U. S. Nat. Herb. 16: 



175. 1913. 

 Houstonia angustifolia rigidiuscula A. Gray, Syn. Fl. 2': 27. 1878. 

 Type locality: Texas. 



Range: Western Texas and southern New Mexico to Mexico. 

 New Mexico: Tucumcari; Lincoln; Queen; James Canyon. Upper Sonoran 

 Zone. 



6. Houstonia rubra Cav. Icon. PI. 5: 48. pi. 474. 1799. 



Hedyotis rubra A. Gray, Mem. Amer. Acad. n. ser. 4: 61. 1849. 



Oldenlandia rubra A. Giuy, PI. Wright. 2: 68. 1853. 



Type locality: "Habitat prope oppidum mexicanum Ixmiquilpan." 



Range: New Mexico and Arizona to Mexico. 



New Mexico: Puertecito; Zuni; Albuquerque; Santa Fe; Fort Wingate; Socon-o 

 Mountain; Apache Teju; Round Moimtain; East View; Buchanan. Dry hills and 

 plains, in the Upper Sonoran Zone. 



