FLOWERIXG PLANTS AND FERNS OF ARIZONA 787 



1. LYCIUM. 35 Desert-thorn 



Plants shrubby, usually spiny; leaves mostly fascicled, the blades 

 entire; flowers chiefly axillary, solitary or in small clusters; calyx 

 campanulate, irregularly toothed or cleft ; corolla campanulate, tubular- 

 funnelform, or salverf orm ; stamens 4 or 5; style slender, the stigma 

 capitate or 2-lobed; berry fleshy or dry, globose or ovoid, subtended by 

 the persistent calyx. 



These plants, also known as squawberry, tomatillo, and wolfberry, 

 have contributed to the subsistence of the Indians. Several of the 

 species produce abundant quantities of insipid, slightly bitter, juicy 

 berries that are eaten raw or prepared as a sauce. Probably all of the 

 native species furnish winter forage for livestock. They grow com- 

 monly along washes and on dry slopes, in desert or semidesert areas. 

 Some of the species tolerate a rather high degree of soil salinity. All 

 of the Arizona species, with the possible exception of L. pallidum, 

 shed their leaves and become dormant during periods of drought, 

 refoliating quickly when conditions become favorable. They flower 

 regularly in spring, often again after summer rains. 



Key to the species 



1. Twigs tomentose when young; fruit transversely constricted, the upper part 

 dry, bony, brown (2). 

 2. Fruit constricted below the middle; calyx lobes subulate or linear, equaling to 

 twice as long as the tube; corolla glabrous 1. L. macrodon. 



2. Fruit constricted above the middle; calyx lobes from one-third to as long as 



the tube; corolla densely pubescent to glabrous 2. L. cooperi. 



1. Twigs not tomentose; fruit a plump, succulent, scarlet berry, or (in L. cali- 

 fornicum) the endocarp hardened (3). 



3. CaLyx tube densely glandular-pubescent; leaves, except in age, abundantly 



glandular-pubescent (4) . 

 4. Calyx campanulate to turbinate, the lobes longer than the tube and 

 rounded, to one-half as long as the tube and acute; berry 7- to 20-seeded; 



corolla lobes purple; foliage often cinereous 5. L. parishii. 



4. Calyx cylindric, or turbinate in small-flowered forms, the lobes rarely 

 more than one-quarter as long as the tube; berry usually many- 

 seeded; foliage not cinereous; plants sexually dimorphic (5). 

 5. Filaments densely villous on the lower half of the free portion; corolla 



lobes pale lavender; flowers mostly pendulous 6. L. exsertum. 



5. Filaments glabrous or sparsely villous at base of the free portion; 



corolla lobes purple; flowers not pendulous 7. L. fremoxtii. 



3. Calyx tube glabrous or nearly so; leaves glabrous or slightly scurfy, rarely 

 minutely puberulent (6). 

 6. Corolla greenish white, the tube 15 to 20 mm. long, greatly expanded 

 above the middle, the mouth 5 to 6 mm. in diameter; leaves large, 



pallid ; berry glaucous. 4. L. pallidum. 



6. Corolla ochroleucous, the lobes pale lavender or pinkish; corolla tube 4 to 

 15 (rarely 18) mm. long, if greatly expanded then less than 10 mm. 

 long (7). 

 7. Corolla lobes finely lanate-ciliate; corolla tube funnelform, 8 to 15 mm. 



long 8. L. TORRE YI. 



7. Corolla lobes glabrous or sparsely ciliate (8) . 



8. Corolla lobes one-half to as long as the tube, normally 4; corolla 

 tube 1 to 5 (usually 2 or 3) mm. long; leaves very succulent and 

 thickened, often pyriform, less than 10 mm. long; fruit with a 

 hardened endocarp, 2 to 4 mm. long; seeds 2. 



3. L. CALIFORNICUM. 



8. Corolla lobes one-sixth to one-third as long as the tube; fruit entirely 

 succulent, 3 to 8 mm. long; seeds several to many (9). 



Reference: Hitchcock. C. Leo. a monographic study of the gents lycium of the western 

 hemisphere. Mo. Bot. Gard. Ann. 19: 179-374. 1932. 



