Choisya. RUTACE^. 371 



Pistil of a single carpel on a small cupulate disk ; ovary globular, with a pair of ascending 

 ovules ; style suprabasal, clavellate ; stigma subcapitate. Fruit globose, pea-shaped, thiu- 

 drupaceous, a narrow layer of pulp between the smooth epicarp and a parchment-like 

 endocarp ; seed globular, with a thick crustaceous testa, campy lotropous ; embryo almost 

 annular in a very thin stratum of fleshy albumen ; cotyledons oval, rather fleshy, longitudi- 

 nally convolute-infolded. Simple-leaved shrub. 



Tribe III. AMYRIDE^. Shi'ubs or trees, balsamic-resinous, with hermaphrodite 

 or polygamous flowers, and a solitary carpel with a terminal sessile stigma. Ovules 

 a pair, collateral. Embryo straight, with very thick cotyledons ; no albumen. 



7. AMYRIS. Calyx 4-toothed, persistent. Petals 4, imbricated in the bud, at length widely 

 spreading. Stamens 8, those opposite the petals shorter. Stigma sessile or subsessile, 

 depressed-capitate. Drupe globular, with thin flesh and chartaceous putamen, 1-seeded. 



Tribe IV. AURANTIEiE. Trees or shrubs, aromatic (fragrant with volatile oil), 

 with hermaphrodite flowers. Stamens often 3 or 4 times as many as petals or 

 somewhat indefinitely numerous, then disposed to be irregularly polyadelphous. 

 Pistil of few or several cells or carpels completely combined, both as to ovary and 

 style (the latter deciduous) ; ovules not rarely several in each cell. Fruit baccate 

 and corticate ; seeds destitute of albumen. Leaves 1-several-foliolate. Wholly 

 of the Old World. The familiar genus is 



8. CITRUS. Flowers 4-8 (mostly 5)-merous. Calyx cupular. Petals narrowly oblong, 

 thickish, imbricated in the bud, deciduous. Stamens 20 to 60, inserted around a strong 

 annular or cupular disk. Ovary several-celled and several ovules in each cell. Embryo 

 straight, with short radicle and fleshy cotyledons; in cultivation not rarely two or more 

 embryos developed in each seed. 



1. THAMNOSMA, Terr. & Frem. (©a/Avos, a bush, oo-/x7^, scent or bad 

 smell.) — Rue-scented low-shrubby or nearly herbaceous pustulate-dotted plants, 

 with small simple sessile alternate leaves, and somewhat racemiform inflorescence 

 at ends of rigid branches. Petals yellowish or purplish-tinged. — Frem. Rep. 

 313 ; Torr. Pacif. R. Rep. iv. 73, t. 3 ; Benth. & Hook. Gen. i. 288 ; Brew. & 

 Wats. Bot. Calif, i. 97. Rutosma, Gray, PI. Lindh. pt. 2, 158. 



T. montana, Tore. & Frem. 1. c. Shrubby, broom-like : rigid branches pustulate, largely 

 leafless : leaves very small, linear or broader, few or deciduous : petals half inch long, mostly 

 erect, purple : filaments and style filiform, the latter exserted : ovary and capsule didymous, 

 almost bifollicular at maturity, raised on a slender but occasionally short stipe ; seeds few or 

 by abortion solitary, somewhat cochleate-reuiform, the coat nearly smooth ; cotyledons 

 linear. — Desert-region of Arizona and adjacent borders of Utah and California ; first coll. 

 by Fremont. 



T. Texana, Torr. Herbaceous from a woody base : stems slender, erect or spreading, a 

 foot or less high, leafy : leaves filiform-linear, half inch long : petals 2 lines long, ovate- 

 oblong, spreading, pale greenish-yellow or whitish or purplish outside : style not exserted : 

 .stipe of deeply obcordate fruit very short or hardly any ; seeds several, globular-reniform, 

 muriculate-papillose ; cotyledons oblong. — Bot. Mex. Bound. 42; Brew. & Wats. I.e.; 

 Coulter, Man. Rocky Mt. Reg. 45. Rutosma Texana, Gray, 1. c, Gen. 111. ii. 144, t. 155, & 

 PI. Thurb. 298, 304. — Rocky hills, Texas to S. Colorado and Arizona ; first coll. by Berlan- 

 dier. (Adj. Mex., Gregg, &c.) 



2. CHOtSYA, HBK. (/. B. Choisy, Genevese botanist.) — Branching 

 shrubs of Mexico and adjacent Arizona, glandular-punctate and aromatic, some- 

 what pubescent, with chiefly opposite palniately 3-9-foliolate leaves and sessile 

 leaflets, and rather showy white or cream-colored flowers somewhat umbellately 

 cymose at the summit of leafy branches. — Nov. Gen. & Spec. vi. 4, t. 513 

 (gynoecium incorrect); DC. Prodr. i. 724 (where char. " capsula 5-rostrata" 



