POLYPETALOUS EXOGENOUS PLANTS. 289 



borne on two parietal placentae. — Perennial herhs, with 

 broadly cordate and lobed leaves^ and small flowers in a 

 terminal raceme. 



M. DiPHYLLA, L. Hairy ; radical leaves cordate, acute, 

 coarsely serrate and slightly 3-lobed, on long petioles ; stem- 

 leaves 2, opposite, sessile ; raceme slender, loosely many- 

 flowered. Shady woods. Stem 6-12' high ; flowers white. 



CHRYSOSPLENIUM, Tonrn. Golden Saxifkage. 



Calyx-iwhe coherent with the ovary, 4-5-lobed, the lobes 

 obtuse and yellow within ; petals none ; stamens 8-10, very 

 short, inserted on a conspicuous disk; styles 2; capsule 

 very short, 2-lobed, 1-celled, with 2 parietal placentae, 

 2-valved at the apex, many-seeded. — Smooth and succulent 

 herhs, with roundish leaves, and axillary flowers. 



C. Ameeicanum, Schweinitz. ^S/fems prostrate, forking ; 

 leaves mostly opposite, roundish, slightly lohed ; flotuers 

 solitary, greenish ; perennial. 



HYDRANGEA. 



Calyx-iuhe hemispherical, 8-10-ribbed, coherent with the 

 ovary, the limb 4-5-toothed, persistent ; jjetals ovate, val- 

 vate in the bud; stamens 8-10, filiform; capsule crowned 

 with the 2 diverging styles, 2-celled, many-seeded, opening 

 at the apex between the styles. — Erect sJiriibs, with opposite 

 petioled leaves, without stipules, and whitish or purplish 

 flowers, in ample compound cymes ; the marginal flowers 

 mostly sterile, with the calyx-lobes enlarged and showy. 



H. arborescens, L. Smoothish ; leaves ovate, acute or 

 acuminate, serrate, mostly rounded or cordate at the base ; 

 cymes crow^ded, flat-topped ; sterile flowers few or none. — 

 8hruhy 4°-8° high ; leaves 3 -C long. 



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