SENNA FAMILY 479 



green; petioles slender, 15-20 mm. long; pedicels 10-15 mm. long; pods 5-6 cm. long, about 

 15 mm. wide, very thin. 



Foothill slopes, Upper Sonoran Zone; Siskiyou Mountains, south through the Coast Ranges and the Sierra 

 Nevada to San Diego County, California, east to Utah and western Texas. Type locality: "rocky drains of the 

 Upper Guadaloupe," Texas. April-May. 



2. CASSIA [Tourn.] L. Sp. PL 376. 1753. 



Trees and shrubs or herbaceous plants, with evenly pinnate leaves, and usually yellow 

 flowers. Calyx deeply toothed or divided into nearly equal lobes. Petals 5, nearly equal, 

 spreading, clawed, imbricate. Stamens 10 or sometimes 5, _ often unequal; anthers all 

 alike or those on the lower stamens longer, opening by terminal pores. Ovary sessile or 

 stipitate; ovules many. Pods flat or terete, often curved, sometimes septate between the 

 seeds. [Ancient Greek name.] 



About 200 species of warm temperate and tropical regions. Type species, Cassia fistula L. 



Leaf-rachis much prolonged beyond the last pair of leaflets and sharp-pointed; herbage finely and usually sparsely 



puberulent, appearing glabrous except under a lens. 1- C. armata. 



Leaf-rachis not prolonged beyond the leaflets; herbage densely white-pubescent. 2. C. Covesii. 



1. Cassia armata S. Wats. Armed Senna or Cassia. Fig. 2549. 



Cassia armata S. Wats. Proc. Amer. Acad. 11: 136. 1876. 

 Xerocassia armata Britt. & Rose, N. Amer. El. 23: 246. 1930. 



Low much branched shrub, 0.5-1.5 m. high, the branches pale green, striate and minutely 

 puberulent, fistulous. Stipules none; leaves very sparse, pinnate, the rachis dilated ending in a 

 prolonged sharp point, 5-7 cm. long; leaflets only 1-4 pairs, remote, obliquely oblong, 4-6 mm. 

 long, nearly glabrous; racemes 5-15 cm. long, leafy-bracted ; pedicels slender, 10-15 mm. long; 

 petals broadly ovate, 8-12 mm. long, salmon-colored ; pods short-stipitate, 25-40 mm. long, 4-5 

 mm. thick, minutely appressed-puberulent. 



Dry desert washes and slopes, Lower Sonoran Zone; Mojave and Colorado Deserts, California, to central 

 Arizona. Type locality: "Between Fort Mojave and Cajon Pass," California. April-June. 



2. Cassia Covesii A. Gray. Coves's Cassia. Fig. 2250. 



Cassia Covesii A. Gray, Proc. Amer. Acad. 7: 399. 1868. 

 Earleocassia Covesii Britt. & Rose, N. Amer. Fl. 23: 249. 1930. 



Low suffrutescent plants, 3-6 dm. high, clothed throughout with a dense white pubescence, 

 the stems leafy, branching at the base from a woody caudex. Stipules filiform ; leaf-rachis 25-35 

 mm. long; leaflets 2 or 3 pairs, obliquely oblong to elliptical, 10-25 mm. long; racemes short, 

 corymbose, the lower pedicels about 2 cm. long ; petals 10-12 mm. long, oblong-obovate, yellow ; 

 pods 2-3 cm. long, straight or slightly curved. 



Sandy desert washes, Lower Sonoran Zone; Chuckwalla Mountains, southern California, to Arizona. Type 

 locality : Camp Grant, and south of Prescott, Arizona. April-Aug. 



Parkinsonia aculeata L. Sp. PI. 375. 1753. Small tree 6-9 m. high, with smooth light green bark. 

 Petioles very short or none, subtended by stout 1-3-forked spines; pinnae 1 to several, their rachis flattened, often 

 20 cm long or more; leaflets scattered, sometimes very scanty, 4-10 mm. long; flowers racemose; petals 10-15 mm. 

 long the blades rounded or oval; pods 5-10 cm. long, constricted between the seeds, and acuminate at both ends. 

 In sandy alluvial soils, Lower Sonoran and Tropical Zones; southwestern Arizona to Florida, and widely dis- 

 tributed in the tropics. Probably not native in California, but widely planted in the Colorado Desert region of 

 Riverside and Imperial Counties, and sometimes growing spontaneously. Palo Verde. 



3. CERCIDIUM Tulasne, Arch. Mus. Paris 4: 133. 1844. 



Shrubs or small trees with smooth bark, the branches often armed with spines.^ Leaves 

 bipinnate, distinct from the spines, the rachis of the pinnae terete. Flowers in short 

 corymbose clusters. Calyx-lobes short, valvate. Petals 5, yellow, with broad imbricated 

 blades. Stamens 10, slightly declined, the filaments pubescent near the base. Pods flat- 

 tened or torose, the seeds several. [Name Greek, a weaver's instrument, which the shape 

 of the pod suggests.] 



An American genus of 8 to 10 species. Type species, Cercidium spinosum Tulasne. 



Branches spine-tipped but not armed with spines; leaflets minute, 1-2; mm. long; pods torose. . 



1. C. microphyllum. 



Branches armed with short spines; leaflets 4-7 mm. long; pods flattened. 2. C. ftoridnm. 



1. Cercidium microphyllum (Torr.) Rose & Johnston. Small-leaved Palo Verde. 



Fig. 2551. 



Parkinsonia microphylla Torr. Pacif. R. Rep. 4: 82. 1857. 



Cercidium microphyllum Rose & Johnston, Contr. Gray Herb. 70: 66. 1924. 



Cercidiopsis microphylla Britt. & Rose, N. Amer. Fl. 23: 306. 1930. 



Arborescent shrub or small tree, 2-8 m. high, with smooth light gray-green bark, the branch- 

 lets spine-tipped but without lateral spines. Leaves without a primary rachis, the two sessile 

 pinnae 1-3 cm. long; leaflets 4-8 pairs, elliptic, 1-2 mm. long; pedicels 5-15 mm. long; petals 

 yellow, 5-7 mm. long ; pods 4-6 cm. long, scarcely flattened, 1-4-seeded, much restricted between 

 the seeds, ending in a long acuminate beak, narrowed to a stipe at the base. 



Desert regions, Lower Sonoran Zone; Whipple Mountains, California, to Arizona and Sonora. Type 

 locality: diluvial banks, Yuma, Arizona. March-May. Horse Bean. 



