ZYGOPHYLLACE^i 579 



winged, separating at maturity into 5 indehiscent carpels. Seeds solitary or 

 in pairs in each cell ; seed-coat thick and fleshy ; embryo straight or nearly 

 so ; cotyledons oval, foliaceous ; radicle short, superior. 



Of the fourteen genera of this family, mostly confined to the warmer parts 

 of the northern hemisphere, one only, Guaiacum, has an arborescent repre- 

 sentative in the United States. 



1. GUAIACUM, L. Lignum-vitae. 



Trees or shrubs, with scaly bark, and stout terete alternate branchlets often with 

 swollen nodes. Leaves petiolate, abruptly piunate, with 2-14 entire reticulate- 

 veined leaflets, and minute mostly deciduous stipules. Flowers terminal, solitary or 

 uubellate-fascicled, pedunculate, from the axils of minute deciduous bracts; calyx- 

 lobes slightly united at the base, unequal, deciduous; petals broadly obovate, more 

 or less unguiculate; stamens inserted on the inconspicuous elevated disk opposite to 

 and alternate with the petals; filaments filiform, naked or bearing at the base on 

 the inner surface a minute membranaceous scale; anthers oblong; ovary raised on 

 a short thick stalk, obovate or clavate, 5-lobed, contracted into a slender subulate 

 acute style; ovules 8-10 in each cell, suspended in pairs from the inner angle. Fruit 

 fleshy, 5-celled, smooth, coriaceous, narrowed at the base into a short stem, with 

 5 wing-like angles, ventrally and sometimes dorsally dehiscent. Seeds suspended, 

 ovoid; seed-coat easily separable from the hard bony nucleus closely invested with 

 a thin indistinct tegumen. 



Guaiacum is confined to the New World, and is distributed from southern Florida 

 through the Antilles, Mexico, and Central America to the Andes of Peru. Seven or 

 eight species are distinguished. 



Guaiacum produces heavy close-grained wood, the cells of the heartwood filled 

 with dark-colored resin. The lignum-vitae of commerce, largely used for the sheaths 

 of ship-blocks, mallets, skittle-balls, ten-pin balls, etc., is produced principally by 

 Guaiacum ojficinale, L., of the Antilles and South America, and by Guaiacum sanc- 

 tum, L. Guaiacum resin is a stimulating diaphoretic sometimes used in the treatment 

 of gout and rheumatism. 



The generic name is from the Carib Guaiaco or Guayacon, the aboriginal name of 

 the Lignum-vitse. 



1. Guaiacum sanctum, L. 



Leaves 3'-l' long, with 3-4 pairs of obliquely oblong or obovate mucronate sub- 

 sessile leaflets, membranaceous,light green and puberulous below when they first ap- 

 pear, becoming subcoriaceous, glabrous, dark green and lustrous on both surfaces, 

 1' long and nearly ' wide, persistent until the appearance of the new growth in 

 March or early April; stipules broadly acuminate, tipped with a short mucro, pubes- 

 cent, I' long, usually caducous, but sometimes persistent during the season. Flowers 

 f ' in diameter, opening almost immediately after the appearance of the new growth, 

 and continuing to open during several weeks, solitary on slender pubescent peduncles 

 shorter than the leaves and usually produced 3 or 4 together at the end of the 

 branches from the axils of the upper leaves, their bracts acuminate, minute, the 2 

 lateral rather smaller than the others; calyx-lobes obovate, slightly pubescent, espe- 

 cially on the outer surface near the base, and smaller than the blue petals twisted 

 below from left to right, and thus appearing to be obliquely inserted ; filaments 

 naked; ovary obovate, prominently 5-angled, glabrous, contracted at the base into 



