58 AESCULACEAE 



typical species are found in southern Oregon and in the Siskiyou Mountains, California. Type locality: "Cali- 

 fornian Sierra at middle altitudes." 



Acer glabrum var. diffusum (Greene) Smiley, loc. cit. (.Acer diffusum Greene, Pittonia 5: 2. 1902; Acer 

 bernardinum Abrams, Torreya 7: 219. 1907.) Low diffusely branched shrub, with nearly white bark. Leaves 

 often trifoliolate, 1-2.5 cm. long, teeth often obtuse or subcrenate; samara-wing 10-12 mm. long. Alpine stream 

 banks and rocky slopes, Boreal Zones; western Nevada, southern Sierra Nevada, San Bernardino and San 

 Jacinto Mountains, California. Type locality: west Humboldt Mountains, Nevada. 



3. Acer circinatum Pursh, Vine Maple. Fig. 3097. 



Acer circinatum Pursh, Fl. Amer. Sept. 1:267. 1814. 

 Acer modocense Greene, Pittonia 5: 4. 1902. 



An erect shrub or small tree attaining a height of 10-15 m. but more often reclining or vine- 

 like. Leaves short-petioled, 7-12 cm. broad, round-cordate in outline, with a broad and usually 

 shallow sinus, 7-9-lobed, the lobes acuminate and sharply serrate, villous when young, glabrate 

 in age except for a tuft of hairs near the base beneath ; corymbs terminal on slender 2-leaved 

 branchlets, 5-20-flowered ; calyx-lobes 4-6 mm. long, villous, reddish purple ; petals much 

 shorter than the calyx-lobes, greenish white ; stamens 8, the filaments villous below ; samaras 

 2-3 cm. long, widely diverging to form an angle of 180 degrees, scarlet when ripe. 



Stream banks and moist woods. Humid Transition Zone; west of the Cascade Mountains from British 

 Columbia to Mendocino and Butte Counties, California. Type locality: Cascades of the Columbia River. April- 

 May. 



4. Acer Negundo subsp. californicum (Torr. & Gray) Wesml. California 



Box Elder. Fig. 3098. 



Negundo californicum Torr. & Gray, Fl. N. Amer. 1 : 250. 1838. 



Acer californicum D. Dietr. Syn. PI. 2: 1283. 1840. 



Acer Negundo subsp. californicum Wesml. Bull. Bot. Soc. Belg. 29: 43. 1890. 



Acer Negundo var. californicum Sargent, Garden & Forest 4: 148. 1891. 



Round-topped tree, 6-20 m. high, the branchlets and foliage pubescent, densely so when 

 young. Leaves 3-foliolate, the terminal leaflet larger than the lateral, 3-5-lobed, or coarsely 

 serrate, rather long-petiolulate, the lateral ones oblong, coarsely serrate or somewhat lobed on 

 the lower edge, short-petiolulate ; staminate flowers borne on elongated, filiform, villous pedicels; 

 calyx minute; stamens 4 or 5; pistillate flowers borne in slender drooping racemes; samaras 

 red when young, becoming straw-colored when mature, about 3 cm. long, finely pubescent. 



Stream banks and moist bottom lands, mainly Upper Sonoran Zone; foothills and valleys from Shasta 

 County to San Bernardino County, California. Type locality: California. Collected by Douglas. March-April. 



Family 88. AESCULACEAE. 



Buckeye Family. 



Trees or shrubs with deciduous, palmately compound leaves. Flowers polyga- 

 mous, showy, borne on jointed pedicels in a terminal thyrse or panicle, the perfect 

 flowers few near the top of the inflorescence, the staminate numerous. Calyx tubular 

 or campanulate, 5-parted, the lobes unequal. Petals 4 or 5, unequal, clawed. Disk 

 entire, often 1 -sided. Stamens 5-8. Ovary 3-celled; ovules 2 in each cell; style 

 slender. Fruit a leathery, globose or slightly 3-lobed capsule, smooth or spiny; 3- 

 celled or by abortion 1-celled and 1-seeded. Seeds large, shining; endosperm none; 

 cotyledons large and thick. 



A family of 3 genera and about 18 species, natives of the northern hemisphere. 



1. AESCULUS L. Sp. PI. 344. 1753. 

 Characters of the family. [The ancient Latin name.] 



A genus of about 15 species, natives of North and Central America and Asia. Type species, Aesculus 

 Hippocastanum L. 



1. Aesculus calif ornica (Spach) Nutt. CaUfornia Buckeye. Fig. 3099. 



Calothyrsus calif ornica Spach, Hist. Veg. 3:35. 1834. 



Aesculus californica Nutt. in Torr. & Gray, Fl. N. Amer. 1: 251. 1838. 



Tree 4-7 m. high, with a broad round top. Leaflets 5-7, oblong-lanceolate, serrulate, 6-15 cm. 

 long, petiolulate, glabrous; thyrse erect, 10-20 cm. long, finely pubescent; calyx 2-lobed, the 

 lobes shallowly toothed; petals white or pale rose, about 15 mm. long; stamens 5-7; anthers 

 orange; fruit smooth, pear-shaped, 1- or rarely 2-seeded, often solitary on the drooping naked 

 rachis of the thyrse ; seed 2-3 cm. in diameter, glossy brown, with a large whitish hilum. 



Hillsides and canyons, especially on north slopes. Upper Sonoran Zone; Coast Ranges and the Sierra 

 Nevada foothills, from Siskiyou County to the Sierra Liebre, Los Angeles County, California. Type locality: 

 California. Collected by Dr. Botta. May. 



