FLOWERING PLANTS AND FERNS OF ARIZONA 581 



the tube; anthers about 2.5 mm. long; styles sparsely hispidulous; 

 capsule with stout teeth along the edges of the valves. 



1. Hermannia pauciflora S. Wats., Amer. Acad. Arts and Sci. Proc. 

 17: 368. 1882. 

 Pima Count}-, Santa Catalina Mountains (Pringle in 1881, the type 

 collection, Lemmon 3069), Tucson Mountains, on dry gravelly slopes 

 (Pringle in 1884), April. Southern Arizona and Sonora. 



3. WALTHERIA 



Plant herbaceous or suffrutescent, tomentose or canescent; flowers 

 in dense axillary clusters; calyx 5-toothed, the teeth shorter than the 

 tube; petals pale yellow, fading reddish; anthers about 1 mm. long; 

 style bearded; capsule pubescent. 



1. Waltheria americana L., Sp. PI. 673. 1753. 



Waltheria detonsa A. Gray, PL Wright. 2: 24. 1853. 



Cochise (?) County and Baboquivari Mountains (Pima County), 

 about 4,000 feet (doubtless elsewhere), canyons, September, type of 

 W. detonsa from southern Arizona (Wright 904). Southern Arizona, 

 Mexico, and widely distributed in tropical America. 



4. AYENIA 



Herbs or undershrubs, resembling some Euphorbiaceae; flowers in- 

 conspicuous; petals with the claw much longer than the blade; 

 staminodia appearing as teeth or lobes at the margin of the expanded 

 apex of the staminal column; capsule 5-celled, conspicuously warty. 



Key to the species 



1. Plant a small, intricately branched shrub; staminal column short, wholly funnel- 

 form; staminodia large, fleshy, crenate; blades of the petals deltoid- 

 reniform, not adnate to the summit of the column, not appendaged dorsally ; 

 ovary and fruit very short-stipitate or subsessile; leaf blades ovate, crenate- 

 dentate 1. A. microphylla. 



1. Plants suffrutescent, or herbaceous above the woody caudex; staminal column 

 slender, elongate, abruptly expanded into the funnelform apical portion; 

 staminodia small, toothlike; blades of the petals not reniform, adnate to 

 the summit of the column, bearing a hornlike dorsal appendage; ovary 

 and fruit distinctly stipitate 2. A. pusilla. 



1. Ayenia microphylla A. Gray, PI. Wright. 1: 24. 1852. 



Near Vail and in the Tucson Mountains (Pima County), Table Top 

 Mountain (Pinal County), 2,000 to 3,000 feet, dry rocky slopes and 

 mesas, spring and late summer. Western Texas, southern Arizona, 

 and northern Mexico. 



A small shrub, less than 0.5 m. high. 



2. Ayenia pusilla L., Syst. Nat. ed. 10, 1247. 1759. 



Gila and Yavapai Counties, south to Santa Cruz and Pima Coun- 

 ties, 2,000 to 4,000 feet, dry hot rocky slopes, March to October. 

 Southern Florida, southern Texas, southern Arizona, southeastern 

 California, and widely distributed in tropical and subtropical America. 



There is much variation in the leaf blades, which vary from nar- 

 rowly lanceolate or oblong-lanceolate to ovate, with crenate-dentate 

 to serrate margins. 



