FLOWERING PLANTS AXD FERNS OF ARIZONA 741 



8. Nutlets lacking a distinct ventral groove or opening in the peri- 

 carp, this usually replaced by an elevated ventral keel (9). 

 9. Plant annual; nutlets attached by a caruncular scar borne 

 upon or at the basal end of the ventral keel, the attach- 

 ment usuallv lateral or suprabasal; nutlets usually rough 

 (10). 

 10. Corolla white; cotyledons entire 9. Plagiobothrys. 



10. Corolla orange or yellow; cotyledons 2-cleft. 



10. Amsinckia. 

 9. Plant perennial; nutlets attached by a broad rounded quite 

 basal noncaruncular attachment; nutlets ovoid, smooth 

 and shiny; corolla orange or yellow (11). 



11. Corolla small, 1 to 4 cm. long; stamens short, included. 



11. LlTHOSPERMUM. 



11. Corolla large, 5 to 6 cm. long; stamens reaching to the 

 corolla sinuses 12. M acromeria. 



1. COLDENIA20 



Low spreading fruticulose plants; leaves small and usually with 

 ovate or elliptic, re volute-margined, pinnately veined blades, the 

 veining usually impressed on the upper surface; corolla funnelform 

 or tubular-fuimelform, white, pink, or lavender, commonly opening 

 late in the afternoon. 



Key to the species 



1. Fruit depressed-globose and unlobed until completely mature, bearing the 

 style on its rounded summit, finally breaking up into quarters to form the 

 nutlets; leaves ovate to elliptic, white-tomentose, obscurely veined; 

 flowers borne singly in the leaf axils or at the forks of the stem. 



1. C. canescen-s. 

 1. Fruit parted into distinct nutlets even in the bud, bearing the style between 

 the apices of the nutlets (2). 

 2. Leaf blades not evidently nerved, lanceolate to linear, usually very con- 

 spicuously and pungently setose: base of the petiole expanded, indurate, 

 usually distinctly villous; flowers solitary in the leaf axils; nutlets 

 finely warted, ovate, the inner face somewhat angled. 



2. C. HISPIDISSIMA. 



2. Leaf blades with evident impressed nerves, ovate or obovate to nearly orbic- 

 ular, lacking conspicuous setae, strigose or merely short-hispid; base 

 of the petiole not expanded, or indurate, or villous; flowers in dense 

 clusters at the forks of the stem; nutlets smooth or merely granulate (3). 

 3. Plant annual; corolla pink or white; sepals with short pungent hairs; 

 style surpassed by the calyx; cotyledons horseshoe-shaped. 



3. C. XUTTALLII. 



3. Plant perennial; corolla blue or bluish; sepals merely villous; style sur- 

 passing the calyx; cotyledons ovate or suborbicular, entire or merely 

 nicked at one end (4). 

 4. Leaves with about 6 pairs of deeply impressed veins; calyx long-villous 

 within; nutlets elongate, with a somewhat angulate inner face. 



4. C. PLICATA. 

 4. Leaves with only 2 or 3 pairs of shallow veins; calyx glabrous or short- 

 pubescent within; nutlets nearly globose 5. C. palmeri. 



1. Coldenia canescens DC, Prodi. 9: 559. 1845. 



Stegnocarpus canescens Torr., U. S. Rpt. Expl. Miss. Pacif. 



2: 169. 1855. 

 Coldenia canescens var. subnuda Johnston, Calif. Acad. Sci. 



Proc. ser. 4, 12: 1137. 1924. 



Grand Canyon, and from southern Yavapai County southward, 

 3,500 feet or lower, frequent on dry sunny mesas and slopes, 



20 Reference: Johnston, I. M. [key to the north American species of coldenia.] Calif. Acad. Sci. 

 Proc. ser. 4, 12: 1139-1141. 1924. 



