72 RUTACE^E. 



ORDER XXV. R U T A C E ^E . 



Represented by a single species of the genus 



PTELEA, Linn. (HOP-TREE). Shrubs or small trees with alternate 

 3-foliolate aromatic pellucid-dotted leaves, and corymbose regular 

 flowers. Sepals, petals and stamens each 4 or 5, the latter inserted out- 

 side of a disk encircling the ovary. Ovary 2-celled, surmounted by a 

 short style, and becoming an orbicular broadly winged 2-seeded samara. 



1. P. crenulata, Greene. Tree 1025 ft. high, strongly aromatic when 

 fresh; glabrous except the tomentulose flowers, and a sparse pubescence 

 on the lower face of the leaves and on the fruit: leaflets cuneate-obovate, 

 obtuse or acute, 1 3 in. long, crenulate or crenate-serrate : filaments 

 villous near the base : samara % in. long and as broad, truncate or 

 emarginate at both ends, often triquetrous and 3-seeded. In the Coast 

 Range, from Lake Co. southward through Contra Costa, etc. May. 



ORDER XXVI. SAPINDACE>. 



Trees or shrubs with opposite compound, or at least deeply lobed 

 leaves, without stipules. Inflorescence compound, usually racemose or 

 thyrsoid. Sepals 5, nearly distinct, or joined into a tubular calyx. 

 Petals 4 or 5, distinct, and, with the few and definite stamens, inserted 

 hypogynously, or around a hypogynous disk. Fruit a 3-celled capsule, 

 or a double samara. Seeds large; without albumen. 



1. ACER, Pliny (MAPLE. BOX-ELDER). Trees or shrubs with oppo- 

 site palmately lobed or pinnately compound leaves without stipules. 

 Flowers small, greenish or reddish, in terminal racemes, umbel-like 

 corymbs, or fascicles, perfect or unisexual. Calyx usually 5-lobed. 

 Petals 5 or 0. Stamens usually 8 (312), in the perfect flowers inserted 

 with the petals upon a lobed disk. Ovary 2-lobed, 2-celled; styles 2. 



* Leaves simple; tree not dioecious. 



1. A. macrophyllum, Pursh. Tree 5090 ft. high, 23 ft. in diam- 

 eter: leaves % 1 ft. broad, deeply 5-lobed, the sinuses rounded, the 

 segments often 3-lobed, coarsely toothed: fl. large, in large crowded 

 pendulous racemes which appear with the unfolding leaves, greenish 

 yellow or reddish: stamens 9 or 10; filaments hairy: fruit densely hir- 

 sute or almost hispid, the glabrous wings 1 in. long or more, divergent. 

 Along mountain streams or on hillsides. 



* * Leaves unequally pinnate; tree dioecious. 



2. A. < :il i lorn ic 11 m (T. & G.), Dietr. Tree 3070 ft. high, the young 

 twigs and partly developed leaves villous-canescent: leaflets 3, ovate, or 



