FLOWERING PLANTS AND FERNS OF ARIZONA 515 



1. CHOISYA. Starleaf, Zorillo 

 Contributed by C. H. Muller 



Aromatic shrubs, often prominently glandular; leaves opposite, 

 3- to 7- or more-foliolate, the leaflets digitate, linear, prominently 

 glandular on the margins and petioles; flowers solitary in the axils 

 but crowded toward the tips of the stems; sepals 5, glandular and 

 ciliate; petals 5, at least 1 cm. long, white, glabrous; stamens 10, in 

 2 series of alternating unequal filaments; ovary of 5 united pubescent 

 carpels with glabrous glandular tips; styles adnate above, the lobed 

 stigma capitate; fruit of 2 or 3 pubescent and glandular carpels, the 

 glandular tips migrating to form dorsal protuberances, the persistent 

 style bases forming apical points; seeds oval or reniform, reticulately 

 pitted. 



The Arizona species belong to the subgenus Astrophyllum, regarded 

 by some botanists as a distinct genus. 



Key to the species 



1. Herbage appressed-hirtellous or partly glabrate: leaflets narrowly linear, 1 to 

 2 (rarely 3) mm. wide, deeply re volute, the petioles always less than 

 one-third the length of the leaflets: glands prominent 1. C. arizoxica. 



1. Herbage spreading-pilose; leaflets broadly linear, 3 to 5 mm. wide or rarely 

 narrower, minutely revolute, flat and willowlike, the petioles always 

 half as long as the leaflets or longer; glands scarcely prominent. 



2. C. MOLLIS. 



1. Choisya arizonica Standi, Biol. Soc. Wash. Proc. 27: 222. 1914. 

 Mule and Dragoon Mountains and Coronado National Forest 



(Cochise County), Santa Rita Mountains (Pima County), seldom 

 above 5,500 feet, dry, shrubby slopes, May to July, type from the 

 Santa Rita Mountains (Pringle in 1884). Known only from south- 

 eastern Arizona. 



An attractive shrub, 3 to 6 feet high. 



2. Choisya mollis Standi., Biol. Soc. Wash. Proc. 27: 223. 1914. 

 Mountains of Santa Cruz County near Xogales and Ruby, 3,500 to 



4.000 feet, dry slopes and sides of canyons, type collected by Schott 

 in the Pajarito Mountains (Santa Cruz County, or adjacent Sonora). 

 Known definitely only from southern Arizona. 



A shrub 3 to 5 feet high, with leaflets resembling the leaves oiSalix 

 taxifolia H. B. K. 



2. THAMXOSMA 



Plants shrubby to herbaceous or nearly so; leaves simple, alternate? 

 narrow, entire, persistent or soon deciduous; flowers in small cymose 

 or racemose clusters; corolla cvlindric to campanulate; capsule deeply 

 2-lobed. 



Key to the species 



1. Plant shrubby, more or lese spinescent: herbage yellowish: leaves mostly 

 linear-spatulate, few, soon deciduous: corolla cylindric-funnelform or 

 slightly urceolate, 8 to 14 mm. long; petals dark blue: stipe of the capsule 

 longer than the calyx; seeds 4 to 6 mm. long, smooth or somewhat rugose. 



1. T. MONTANA. 



1. Plant suffrutescent or nearly herbaceous, not spinescent; herbage glaucous- 

 green; leaves linear to nearly filiform, numerous, persistent; corolla cam- 

 panulate, 3 to 5 mm. long; petals yellowish, or brownish purple; stipe of 

 the capsule shorter than the calyx, or none; seeds not more than 2 mm. 

 long, tuberculate 2. T. texaxa. 



