FLOWERING PLAXTS AND FERNS OF ARIZONA 667 



3. Plants dark green or reddish; scapes less than 10 cm. long or, if slightly more 

 than 10 cm. long, then more than twice as long as the pedicels (4). 

 4. Scapes not more than 3 cm. long; pedicels few, relatively short and stout. 



Var. SUBUMBELLATA. 



4. Scapes 5 cm. long or longer; pedicels numerous (5). 



5. Calyx glabrous or nearly so; pedicels sparsely puberulent. 



var. DIFFUSA. 



5. Calyx copiously to densely puberulent at base of the tube and on the 



lobes; pedicels usually densely puberulent__ var. puberulexta. 



The varieties intergrade and are difficult to distinguish. The 

 typical form of the species apparently does not occur in Arizona, but 

 var. glandulosa (Woot. and Standi.) St. John (A. glandulosa Woot. 

 and Standi.) has been collected several times in the region of Flagstaff 

 and the San Francisco Peaks and in the White Mountains. The 

 var. subulijera A. Gray (A subulijera Rydb.) is reported from Pres- 

 cott, and a form intermediate between var. subulijera and var. glandu- 

 losa from the base of the San Francisco Peaks. The var. subumbellata 

 A. Nels. (A. subumbellata Small) occurs at higher altitudes than any 

 other form, ascending to 12,000 feet on the San Francisco Peaks. 

 By far the most abundant and widely distributed of the Arizona 

 forms is var. diffusa (Small) Knuth (A. diffusa SmaU), which occurs 

 throughout the range of the species in Arizona. The var puberulenta 

 (Rydb.) Knuth (A. puberulenta Rydb.) is not known definitely to 

 occur in Arizona, but specimens from the Kaibab Plateau and the 

 vicinity of Flagstaff have been so identified. 



3. SAMOLUS. Waterpimperxel 



Plants mostly perennial, glabrous or nearly so; stems leafy, at least 

 below; leaf blades broad, entire; flowers smaU, pedicelled, in loose 

 racemes or panicles, the petals white; capsule globose, opening 

 apically by valves. 



Key to the species 



1. Leaves crowded near the base of the stem, the blades broadly spatulate; 

 pedicels bractless, ascending, rather stiff; corolla 3 mm. long or longer. 



1. S. ebracteatus. 



1. Leaves scattered along the stem, the blades oval, elliptic, or somewhat obovate; 



pedicels bearing a small bract, spreading, lax; corolla less than 3 mm. 

 long (2). 



2. Stems erect or ascending, bearing several or numerous leaves; blades of the 

 basal leaves commonly oval or elliptic; inflorescences several- to many- 

 flowered; bract borne near the middle of the pedicel; calyx lobes shorter 

 than the tube 2. S. floribuxdu>. 



2. Stems mostly procumbent, stolonlike, bearing few leaves; blades of the basal 

 leaves obovate or spatulate; inflorescences few-flowered; bract borne 

 usually near the base of the pedicel; calyx lobes equaling or longer than 

 the tube 3. S. vagaxs. 



•1. Samolus ebracteatus H. B. K., Nov. Gen. et Sp. 2: 223. 1817. 

 Not known definitely from Arizona but has been collected along 

 the Muddy River, Nevada, near the northwestern border. Florida 

 to Texas, southern Nevada; Mexico, West Indies. 



2. Samolus floribundus H. B. K., Nov. Gen. et Sp. 2: 224. 1817. 

 Navajo, Yavapai, Greenlee. Pinal, and Pima Counties, 1.200 to 



5,000 feet, wet soil along streams, April to August. Throughout 

 most of North America; South America. 



