356 ZYGOPHYLLACEiE. Guaiacum. 



Zijgophyllum tridentatum, Moc. & Sesse ace. to DC. Prodr. i. 706; A. DC. Calcjues des Dess. 

 t. 159.^ — Arid districts, S. Texas'- to S. Utah and S. California; fl. summer. (Mex.) 



5. GUAlACUM, Plumier. LiGNUM-vixiE. (Aboriginal name.) — Trop- 

 ical and subtropical American trees or shrubs, with very hard and heavy resinous 

 wood, abruptly pinnate somewhat coriaceous leaves, and blue or purplish solitary 

 or umbellate-fascicled flowers. — Nov. Gen. 39, t. 17; L. Gen. no. 394; Gray, 

 Gen. 111. ii. 121, t. 148, 149. — Name also written Guajacum, which, however, 

 was not the original form. 



§1. Filaments naked : branchlets much articulated: leaflets comparatively 



large and few, obovate to elliptical. 



G. sanctum, L. (Oue of the two kinds of Lignum-vitce, yieklinf^ Gum Guaiacum). Small 

 tree : leaflets 3 or 4 or rarely 5 pairs, obovate-oblong or elliptical and oblique, inch or less 

 long : petals very short-unguiculate, quarter to third inch long, double the length of the 

 glabrous .sepals : fruit siiort-stipitate, obovate in outline, wing-angled, abruptly pointed, 

 usually all five carpels maturing. — Spec. i. 382 ; Gray, Gen. 111. ii. 123, t. 148 ; Nutt. Sylv. 

 iii. 17, t. 86 (var. parvifo/ium, a small-leaved form) ; Griseb. Fl. W. Ind. 134; Sargent, U. S. 

 10th Census, ix. 28.^ G. verticale (Ort. Dec. viii. 93 ?), A. Rich. Fl. Cub. 321. G. Sloanei, 

 Shuttl. in distr. pi. Rugel, no. 68, 69. — Keys of Florida. (W. Ind.) 



§ 2. Filaments with a small scale at or near the base : leaflets approximate, 



comparatively small, narrow, and more numerous ; stipules in our species small 



and subspinescent. — Porlieria, Ruiz & Pav. Prodr. 55, t. 9. Guaiacum § Guaia- 



cidium, Gray, 1. c. 124, t. 149. 



G. Coulteri, Gray. Shrub 8 to 10 feet high : leaves 3 to 5 pairs, linear-oblong, obscurely 

 veiny, half inch long : fruit 4-5-coccous, retuse .at both ends, mucronulate, half inch high ; 

 the carpels merely carinate on the back. (Flowers not seen.) — PI. Thurb. 312. — Below 

 boundary of Arizona, in Sonora, between Eayon and Ures, Thurber. (Mex., Tk. Coulter* 

 but needs comparison ) 



G.* angustifolium, Engelm.^ Much-branched shrub or small tree, with spinescent 

 branches : leaflets 4 to 8 pairs, oblong-linear or linear-spatulate, quarter to half inch long, 

 reticulated : flowers mostly single, very short-peduncled, 5-merousor occasionally 4-merous : 

 filaments with a short scale at base : ovary 2-celled : fruit somewhat obcordate-bilobed, cari- 

 nate-margined. — I<]ngelm. in Wisliz. 1. c. 113 (p. 29 of reprint) ; Gray, PI. Lindh. pt. 2, 158, 

 & Gen. 111. ii. 124, t. 149. Porlieria angustifolia, Gray, PI. Wright, i. 28; Torr. Bot. Mex. 

 Bound. 42. — S. and W. Texas from the Colorado south and west to the Pecos ; where first 

 coll. by Lindheimer. (Mex., first coll. by Berlandier.) 



^ Tlie nearly related S. American L. divnricnta, Cav., with which this species has recently been 

 united (see A. M. Vail, Bull. Torr. Club, xxii. 229), has, in the four specimens at hand, more narrowly 

 oblong and more widely spreading leaflet.s, which are less inclined to be falcate and are more decidedly 

 connate. In herb. Grav, there is, on the other hand, a specimen collected by Macrce and labelled 

 " Int. Buenos or Chili," which is without doubt identical with L. Mexicnnn. The following synonymj"- 

 may be added to our own species: L. trir/entntn, Coville, Contrib. U. S. Nat. Herb. iv. 75. Zygophyl- 

 luni Californicum, Torr. & Frem. in Frem. Rep. 257, ace. to Coville. Covillea divaricata, A. M. Vail, 

 1. c, not L. divaricata, Cav. 



2 Northward to S. Colorado, ace. to Coulter, Man. Rockj* Mt. Reg. 43. 



3 Add Silv. i. 03, t. 28. 



^ Also about Guaymas, Mex., Palmer. 



5 This species is referred to by Dr. Graj', Proc. Am. Acad. xxii. 306, as " G. parvi folium," while 

 G. parvifolium, Planchon, was unnecessarily given a new name, G. Planchoni, Gray, which must fall 

 into synonymy. 



