164 ROSACEA. Acacia. 



stipules spinescent or inconspicuous ; flowers small, in globose heads or cylindrical 



spikes, on axillary peduncles, yellowish. 



A genus of over 400 species, belonging to the warmer regions of the globe, especially abundant 

 in Australia and Africa. About a dozen are native on the southern borders of the United States, 

 and numerous Australian species are frequent in cultivation. 



1. A. G-reggii, Gray. A small tree 10 to 20 feet high, pubescent with spreading 

 hairs or glabrous, unarmed or with scattered short stout hooked prickles : leaves 

 short, of 2 or 3 pairs of pinnae an inch long : leaflets i or 5 pairs, oblong or oblong- 

 obovate, inequilateral, rounded or truncate at the summit, narrower below, 2 or 3 

 lines long, rather thick and with 2 or 3 straight nerves : flowers in cylindrical spikes 

 an inch or two long, the peduncles equalling or exceeding the leaves : pods com- 

 pressed, curved, 3 or 4 inches long, 5 to 7 lines broad, attenuate at base to a short 

 stipe and acute above, more or less constricted between the seeds ; the thin-coria- 

 ceous valves reticulated : seeds \ inch long, elliptical. — PI. Wright, i. 65. 



San Diego (Cleveland) ; San Felipe Canon (Palmer) ; Fort Mohave (Cooper) ; and eastward to 

 Texas. The species closely resembles A. Wrightii, Benth., of the Rio Grande region, which has 

 a broader and obtuser pod, and usually rather larger leaflets. 



A. Farnesiana, Willd. A small spreading tree, with straight slender stipular spines, pubes- 

 cent or glabrous : pinna? 4 or 5 pairs ; leaflets 10 to 25 pairs, linear, a line or two long, crowded : 

 heads globose : pod oblong, cylindrical, at length turgid and pulpy, 2 or 3 inches long and 6 to 

 lines thick, longitudinally veined. — Widely spread over the subtropical and tropical regions of 

 the New and Old World, and often cultivated for the perfume of its flowers ; native land un- 

 known. About the Missions in the southern part of the State. 



Order XXXII. ROSACEA. 



Herbs, shrubs, or trees, with alternate leaves, usually evident stipules, perigynous 

 mostly numerous stamens, distinct free pistils from one to many, or in one suborder 

 few and coherent with each other and with the calyx-tube into a 2 - several-celled 

 inferior ovary, and anatropous few or solitary seeds destitute of albumen or nearly 

 so : these are the characters of this great order. But the stipules are sometimes 

 evident only upon vigorous shoots, and rarely fail altogether, the stamens are some- 

 times even fewer than the petals or lobes of the calyx, and in a few cases the albu- 

 men of the seed is somewhat copious. — The Californian representatives belong to 

 three great groups, best exhibited as suborders. 



Suborder I. AMYGDALK3E. 



Carpels solitary, or rarely 5, becoming drupes, entirely free from the calyx, this 

 or its lobes deciduous. Ovules 2, pendulous, but seed almost always solitary. 

 Style terminal. — Trees or shrubs, with bark exuding gum, and mostly as well as 

 the seeds yielding the flavor of prussic acid. Stipules free, deciduous. 



1. Prunus. Flowers perfect Carpel solitary. 



2. Nuttallia. Flowers polygamo-dicecious. Carpels and thin-fleshed drupes 5. 



Suborder II. KOSACEiE proper. 



Carpels free from the persistent calyx (the limb of the latter rarely deciduous), 

 becoming akenes, or in the first tribe follicles, or only in Rubus (where they are very 

 numerous) drupe-like in fruit. Stipules commonly adnate to the petiole. Calyx 

 dry and open, or sometimes strictly enclosing the fruit (one or two akenes), or in 

 Rosa fleshy and pome-like enclosing numerous akenes. 



