454 SAPINDACEAE 



ed. 2, 250 (1911), Silva 269, pi. SO, figs. 7-8, and pi. 81 (1910), Man. G12, fig. 613 (1925). 

 Negundo californimm T. & G. Fl. 1:250 (1838), type from Cal., Douglas; 11. & A. Bot. Beech. 

 327, t. 77 (1838) ; Nutt. Sylva, cd. 2, 2:37, t. 72 (1865). 



SAPINDACEAE. Buckeye Family 



Deciduous trees or shrubs with opposite palmately compound leaves and 

 sli<rhtly irregular flowers. Ovary superior, 3-celled with 2 ovules in each cell, 

 commonly but one ovule maturing. — Genera 122, species 1065, all continents, 

 chiefly tropical. 



Bibliog. — Spach, E., Gcnerum et specierum Hippocastaneaium revisio (Ann. Sci. Nat. ser. 

 2, 2:50-64,-1834). Nuttall, Thos., California Horse-Chestnut (Silva N. Am. 2:16-17, pi. 64,— 

 1865). 



1. AESCULUS L. Horse Chestnut 



Flowers showy, ill-scented, on jointed pedicels in a terminal cylindrical thyrse, 

 of two sorts, perfect (fertile) with long thick styles and sterile with short styles; 

 fertile flowers few near top of thyrse. Calyx tubular, unequally 5-cleft. Petals 

 4 or 5, slightlj'- unequal, clawed. Stamens 5 to 7, becoming successively much ex- 

 serted and often unequal. Fruit a large 3-valved capsule releasing one large pol- 

 ished seed. — Species 14, North America, Europe and Asia, temperate. (Latin 

 name of an Italian oak with edible acorns.) 



1. A. californica Nutt. California Buckeye. Low broad-headed tree 10 

 to 20 (or 30) feet high; leaflets 5 to 7, oblong-lanceolate to oblong-elliptic, acute 

 or acuminate, 3 to 5 inches long; thyrse 4 to 6 inches long; petals 6 to 7 lines long; 

 axis of the thyrse at length naked and pendulous, bearing one pear-like pod or 

 sometimes 2 to 9; seed 1 to 2 inches in diameter. 



Foothill country, inhabiting protected hollows or slopes or moister areas in 

 the dry hills, caiion bottoms, stream borders or rich valley flats: Coast Ranges (5 

 to 2500 feet) from Siskiyou Co. to San Luis Obispo Co. and thence south to north- 

 ern Los Angeles Co.; Sacramento Valley; Sierra Nevada foothills (1000 to 5500 

 feet) from Shasta Co. to Kern Co. May- Aug. 



Geog. note.— Aesculus californica is, after Quercus douglasii H. & A., the most common 

 tree in the true foothills of California, although its extreme range is greater than that species. 

 It ia also a widespread tree in the coastal country. Growing close to the sea, as near Salmon 

 Creek, Santa Lucia Mts., at Gazos Creek on the San Mateo coast, or at Capetown near Cape 

 Mendocino, it ranges eastward to the Sierra Nevada foothills. In all the driest hill regions it is, 

 however, absent, as also on the arid plains of the Great Valley, but it is usually found in the 

 hills wherever habitats afford sufficient ground water. It often occurs as a shrub in the chapar- 

 ral (as in the Vaca Mts. or on the forks of the Kaweah River), ascending the gullies on north 

 slopes and spreading out into small fans at their head. In the Redwood belt, as along the upper 

 South Fork of the Eel River, small colonies are found in open or semi-open country at the bases 

 of the hills. In the interior South Coast Ranges, as on the North Fork of Lewis Creek, San 

 Benito Co., it is uncommon and becomes less frequent southward. In the southern Sierra Nevada 

 it keeps to the outer foothill ridges and westerly slopes, and does not invade interior mountain 

 valleys, even where these offer a favorable altitude. 



Biol, note.— The leaf habits, flowering period, and geographic distribution and geographic 

 relationships of Aesculus californica indicate that it is a Pleistocene relic which has gradually 

 adapted itself to the more arid conditions of present day climate in the foothills. The tree comes 

 into leaf in March; by June or early July, on the average, the foliage in most localities away 

 from the coast turns brown under the influence of the high dry season temperatures and intense 

 insolation, a process which is rapid in spite of some protection afforded by conduplication of the 

 leaflets. The leaves fall on turning brown, or they may persist for many weeks, but in any 

 case they cease to function. Usually the leaflets fall separately and in advance of the now de- 

 flexed petioles. Just before the leaves complete their cycle the whole tree is crowned with hun- 

 dreds of heavy panicles of flowers, making it one of the most showy of western arboreous species. 

 Commonly but one or sometimes two of the terminal flowers set fruits, though occasionally one 

 sees as many as 13 chestnuts in a cluster. In starvation years the chestnuts may be eaten by 

 cattle and sometimes cause their death. This is due most probably to the powerful astringency 

 of the fruits in closing the intestinal tract. In the southern Sierra Nevada foothills the wood as 

 used for fence posts is considered more durable than the wood of Sequoia gigantea. Trees of 



