Genus 2. 



LOASA FAMILY. 



5(57 



some species apparently 10, where the outer staminodes are petaloid. Stamens very numerous. 

 Ovary l-celled ; styles 3. Capsule dehiscent at the summit, the placentae with horizontal 

 lamellae between the 2-rowed seeds which are fiat and more or less winged. [In honor of 

 Thomas Nuttall, 1786-1859, American botanist.] 



About 20 species, natives of western North America and Mexico. Type species : Bartonia 

 decapetala Pursh. 



Flowers about 2' broad ; calyx-tube bractless. 



Bracts at base of calyx linear, entire. 



Bracts at base of calyx lanceolate, pinnatifid. 

 Flowers about 4' broad ; calyx-tube bearing bracts. 



1. N. till da. 



2. N. stricta, 



3. N. decapetala. 



I. Nuttallia nuda (Pursh) Greene. 

 Branched Nuttallia. Fig. 2978. 



Bartonia nuda Pursh, Fl. Am. Sept. 328. 1814. 



Mentzelia nuda T. & G. Fl. N. A. i : 535. 1840. 



Nuttallia nuda Greene. Leaflets i: 210. 1906. 



Rough with minute pubescence, slender, i "-5 

 high, often widely branched, the stems light- 

 colored. Leaves all sessile, lanceolate or 

 oblong-lanceolate, acute at the apex, usually 

 sharply and deeply dentate, or the upper pin- 

 natifid, i'-4' long; flowers yellowish white, 

 li'-2' broad, opening in the evening; petals 10, 

 about twice as long as the lanceolate calyx- 

 lobes ; calyx-tube not bracteolate, but l or 2 

 linear, mostly entire bracts at its base; stamens 

 100 or more, the outer ones somewhat petaloid ; 

 capsule oblong, 9"-l2" long, about 3" thick ; 

 seeds numerous, wing-raargined. 



Plains, western Nebraska to Colorado and Wyo- 

 ming. July-.\ug. 



2. Nuttallia stricta (Osterhout) Greene. 

 Stiff Nuttallia. Fig. 2979. 



Hesperastcr strictus Osterhout. Bull. Torr. Club 

 29 : 174. 1902. 



Toutcrea stricta Osterhout ; Rydb. Bull. Torr. 

 Club 30 : 276. 1903. 



Nuttallia stricta Greene, Leaflets i: 210. 1906. 



Similar to the preceding species, but strict 

 and less branched, 3 high or less, the stem 

 white and rough-pubescent. Leaves lanceolate 

 to oblong-lanceolate, obtuse or acute, sinuate- 

 dentate, 3i' long or less, not so deeply toothed 

 as those of N. nuda; flowers several, corym- 

 bose, yellowish white, about 2' broad; stamens 

 numerous, many of the outer filaments petal- 

 oid; calyx-tube not bracteolate, but subtended 

 by lanceolate deeply pinnatifid bracts; capsule 

 i'_ii' long; seeds numerous, about 2" long, 

 wing-margined. 



Plains and hills, South Dakota to Wyoming, 

 Nebraska, Colorado and Texas. June-Aug. 



