20 BURSERACEAE 



2. HOLACANTHA a. Gray. Mem. Amer. Acad. II. 5: 310. 1854. 



Almost leafless shrubs, with stiff thorn-like branchlets. Leaves few, scale-like, de- 

 ciduous. Flowers dioecious, solitary or clustered on the branchlets. Sepals and petals 

 7 or 8. Stamens 12-16 in the staminate flowers, present but sterile in the pistillate. 

 Disk annular, crenulate. Pistil composed of 6-10 slightly cohering carpels tipped by the 

 diverging styles. Fruit of several dry stellately diverging drupes. Seed ovoid. [Name 

 Greek, meaning complete and thorn.] 



A monotypic genus of the arid southwestern United States and adjacent Mexico. 



1. Holacantha Emoryi A. Gray. Crucifixion Thorn. Fig. 3009. 



Holacantha Emoryi A. Gray. Mem. Amer. Acad. II. 5: 310. 1854. 



A much-branched thorny shrub, 2-3 m. high, canescent when young, the thorn-like branchlets 

 stout, terete, 5-15 cm. long. Leaves few, on mature plants reduced to small ovate or subulate 

 scales, on seedlings 10-12 mm. long, linear or lanceolate, entire, repand or with a pair of basal 

 lobes ; flowers usually in dense clusters ; petals, oblong to obovate, 4-5 mm. long, pubescent on 

 the back ; filaments pubescent below the middle ; drupes obliquely ovoid, somewhat compressed, 

 6-8 mm. long. 



Sandy or gravelly soils, Lower Sonoran Zone; rare in California, known stations are: 8 miles west of 

 Ludlow, also at Amboy, Lavic, Dagget, and Goffs, all in southeastern Mojave Desert, and Hayfields, northern 

 Colorado Desert, ranging eastward to Arizona and Sonora. Type locality: on the desert between the Gila River 

 and Tucson, Arizona. April-July. 



Family 77. BURSERACEAE. 



ToRCHwooD Family, 



Aromatic trees or shrubs. Leaves alternate, simple or usually pinnate, deciduous, 

 the rachis often winged. Flowers solitary or often paniculate, perfect or polygamo- 

 dioecious. Calyx 3-5-cleft. Petals as many as the calyx-lobes, distinct or rarely 

 united into a short tube. Stamens twice as many as petals ; filaments naked. Disk 

 annular. Ovary 4-5-celled ; styles distinct, short ; ovules usually 2 in each cell. Fruit 

 drupe-like, containing 1-5 stones. Seeds with membranaceous testa ; endosperm 

 none. 



A family of 19 genera and about 300 species, mainly tropical, in both hemispheres. 



1. BURSERA Jacq. ex L. Sp. PI. ed. 2. 471. 1762. 



Trees or shrubs, with simple or once or twice compound leaves. Flowers solitary 

 in the axils or paniculate, small, polygamous. Calyx-lobes 4 or 5, spreading, persistent. 

 Petals distinct, well exceeding the calyx-lobes, inserted on the edge of the disk. Sta- 

 mens 8-10. Ovary 3-celled. Fruit drupe-like, by abortion sometimes 1-celled, the epicarp 

 splitting into 3 valves ; stones covered with an aromatic pulp. [Name in honor of J. Bur- 

 ser, a botanist of the sixteenth century.] 



An American genus of about 40 species, ranging from California and Mexico to the West Indies and 

 tropical South America. The generic name, although a homonym and antedated by Elaphrium Jacq., has been 

 conserved by the International Rules of Nomenclature. Type species, Bursera gummifera L. 



1. Bursera microphylla A. Gray. Small-leaved Elephant Tree or Torote. 



Fig. 3010. 



Bursera microphylla A. Gray, Proc. Amer. Acad. 5: 155. 1861. 

 Terebinthus microphylla Rose, Contr. U.S. Nat. Herb. 10: 120. 1906. 

 Elaphrium microphyllum Rose, N. Amer. Fl. 25:250. 1911. 



Small tree, the branches glabrous, becoming cherry-red in age. Leaves simply pinnate, the 

 rachis narrowly winged; leaflets 7-33, linear-oblong, 4-8 mm. long, obtuse; flowers appearing 

 before the leaves in 1-3-flowered clusters ; calyx-lobes 1 mm. long, ovate ; petals 4 mm. long ; 

 drupes glabrous, 3-angled, yellow, 6 mm. long. 



Desert regions. Lower Sonoran Zone; locally occurring on the western borders of the Colorado Desert 

 between Fish and Carrizo Creeks, California, and ranging from southern Arizona to Sonora and northeastern 

 Lower California. Type locality: Sierra Tule, Sonora. June-July. 



Melia Azedarach L. Sp. PI. 384. 1753. China-berry or Umbrella Tree. Tree with large twice-pinnate 

 leaves; leaflets ovate to ovate-lanceolate, acute, irregularly serrate or lobed; flowers purplish in large open 

 panicles, petals oblanceolate or linear-oblong; fruit a nearly globular drupe about 1 cm. in diameter. The com- 

 monly cultivated form is the variety umbracutiformis with the numerous branches radiating from the trunk 

 and giving the effect of a huge umbrella. Sometimes growing as an escape in California. Native of Asia, and 

 a member of the family Meliaceae. 



