POLYGONAC^E 311 



Section 3. Flowers perfect or unisexual ; calyx 5-lobed ; 

 ovary superior, 1-celled ; ovule solitary, rising from the bottom 

 of the cell ; fruit inclosed in the thickened calyx ; leaves per- 

 sistent. 



XIII. POLYGONACE^l. 



Trees, with alternate coriaceous stalked leaves, their stipules sheathing the 

 stem. Flowers perfect ; calyx 5-lobed ; stamens 8 ; ovary 3-celled ; ovule 

 orthotropous. Fruit a nutlet, inclosed in the thickened calyx-tube ; seed erect ; 

 embryo axillary in ruminate farinaceous albumen ; radicle superior, ascending, 

 turned toward the hilum. Of this, the Buckwheat family with thirty widely 

 distributed genera, only Coccolobis is arborescent in North America. 



1. COCCOLOBIS, P. Br. 



Trees or shrubs. Leaves coriaceous, entire, orbicular, ovate, obovate, or lanceolate, 

 petiolate, their stipules inclosing the braucli above the node with membrauaceous trun- 

 cate entire brown persistent sheaths. Flowers jointed on ebracteolate pedicels, in 1 

 or few-flowered fascicles subtended by a minute bract and surrounded by a narrow 

 truncate membranaceous sheath, each pedicel and those above it being surrounded 

 by a similar sheath, the fascicles gathered in elongated terminal and axillary racemes 

 inclosed at the base in the sheath of the nearest leaf and sometimes also in a sepa- 

 rate sheath; calyx cup-shaped, the lobes ovate, rounded, thin, and white, reflexed after 

 anthesis, and thickening and inclosing the nut; stamens with filiform or subulate 

 filaments dilated and united at the base into a short discoid cup adnate to the tube 

 of the calyx; anthers ovate, introrse, 2-cell'ed, the cells parallel, opening longitudi- 

 nally; ovary free, sessile, 3-angled, contracted into a short stout style, divided into 

 three short or elongated -stigmatic lobes. Fruit ovoid or globose, rounded or acute 

 and crowned at the apex by the persistent lobes of the calyx, narrowed at the base; 

 flesh thin and acidulous, more or less adnate to the thin crustaceous or bony wall of 

 the nutlet often divided on the inner surface near the base into several more or less 

 intrusive plates. Seed subglobose, acuminate at the apex, 3-6-lobed; testa membra- 

 naceous, minutely pitted, dark red-brown, and lustrous. 



Coccolobis is confined to the tropics of the New World, with about one hundred 

 and twenty species distributed from southern Florida to Mexico, Central America, 

 Brazil, and'Peru. It possesses astringent properties sometimes utilized in medicine. 

 Many of the species produce hard dark valuable wood. 



Coccolobis, from jrrfKKor and \o&6s, is in allusion to the character of the fruit. 



CONSPECTUS OF THE NORTH AMERICAN SPECIES. 



Fruits crowded, in drooping racemes ; leaves broadly ovate to suborbicular, cordate at the 

 base. 1. C. uvifera (D). 



Fruits not crowded, in erect or spreading racemes ; leaves ovate to oblong-lanceolate. 



2. C. laurifolia (D). 



1. Coccolobis uvifera, Jacq. Sea Grape. 



Leaves broadly ovate to suborbicular, rounded or sometimes short-pointed at 

 the apex, deeply cordate at the base, with undulate margins, thick and coriaceous, 

 minutely reticulate-venulose. dark green and lustrous above, paler and puberulous 



