Part 3, 1918] ALLIONIACEAE 189 
5. Pisonia flavescens Standley, Contr. U. S. Nat. Herb. 13: 389. 
1911. 
Branches slender, dark-gray, smooth, the branchlets brown or grayish, puberulent; spines 
stout, straight, 6-7 mm. long; petioles slender, 1-2 cm. long; leaf-blades obovate or obovate- 
oblong, 4-6.5 cm. long, 1.5-3 cm. wide, very acute or attenuate at the base, acute or acuminate 
at the apex, the acumen usually obtuse, subcoriaceous, yellowish-green, concolorous, glabrate 
above, minutely puberulent beneath, the margins plane, the lateral veins evident beneath, 
arcuiate-ascending at an angle of 45-60°; peduncles solitary, 1 cm. long or usually shorter; 
staminate inflorescence capitate-cymose, many-flowered, 1 em. broad or less, the flowers very 
short-pedicellate, the pedicels puberulent; staminate perianth broadly campanulate, 2.5 mm. 
long and usually broader, puberulent, deep-red; stamens usually 6, nearly twice as long as the 
perianth; fruit clavate, 10 mm. long, 3-4 mm. in diameter, 5-angled, glabrate, each angle beset 
with a row of short uniseriate glands. 
TYPE LocaLity: San José del Cabo, Lower California. 
DISTRIBUTION: Vicinity of the type locality. 
6. Pisonia capitata (S. Wats.) Standley, Contr. U. S. Nat. Herb. 
13: 388. 1911. 
Cryptocarpus ? capitatus S. Wats. Proc. Am. Acad. 24: 71. 1889. 
A densely branched shrub or small tree, 5 meters high or less, branched to the ground 
or often with a distinct trunk, the branches spreading or often weak and clambering, armed 
with numerous stout, recurved or rarely straight spines 7-14 mm. long; branches stout, terete, 
gray or greenish-gray, sometimes reddish-brown, the branchlets densely short-villous; petioles 
slender or stout, 0.6-3 cm. long; leaf-blades orbicular or orbicular-obovate, 2-6 cm. long and 
nearly or quite as broad, rounded to broadly cttneate at the base, broadly rounded at the 
apex, or sometimes very shortly and abruptly acutish, thick and firm, dull, yellowish-green, 
densely and finely puberulent on the upper surface, densely puberulent or very sho:t-villous 
beneath, the margins plane, the lateral veins often conspicuous beneath, divaricate or ascend- 
ing; peduncles of the staminate inflorescence solitary, stout, 0.5—-3 cm. long, the cymes sub- 
globose, congested, densely many-flowered, 1-1-8 cm. in diameter, the flowers on very short, 
densely puberulent pedicels, the perianth broadly campanulate, 2-3 mm. long, densely and 
shortly viscid-villous, deep-red, the lobes obtuse; stamens 6, twice as long as the perianth; 
pistillate peduncles 0.5-2 cm. long at anthesis, 4 cm. long or less in fruit, the cymes at anthesis 
subglobose, densely flowered, in age loosely branched, the branches divaricate or ascending, 
the pedicels at first 1-2 mm. long, in age 0.5-2 em. long, the bractlets subulate-linear, 1 mm. 
long, the perianth tubular, 2-2.5 mm. long, densely puberulent, shallowly 5-dentate; fruit 
clavate or prismatic, 7-10 mm. long, 3-4 mm. in diameter, rounded at the apex, narrowed at 
the base, 5-angled, each angle furnished with a row of low uniseriate glands, the sides densely 
puberulent; seed cylindric, 6-8 mm. long, 1.5 mm. in diameter, dark-brown. 
Type LocaLrty: Near Guaymas, Sonora. 
DistRrBuTION: In sandy soil, often along watercourses, southern Sonora to Tepic. 
InLusTRATION: Contr U.S. Nat. Herb. 13: pl. 75, B. 
7. Pisonia Donnell-Smithii Heimer]; Standley, Contr. U. 5. Nat. 
Herb. 13: 387. 1911. 
Branches stout, unarmed, grayish, shortly appressed-pilose, glabrate in age, densely 
leafy; leaves usually crowded on the short lateral branches, very unequal, the petioles 4-8 
mm. long, the blades obovate, obovate-oblong, or elliptic-oblong, 3-5.5 cm. long, 1.2-2.8 cm. 
wide, acute or attenuate at the base, narrowed to the obtuse apex, bright-green, concolorous, 
herbaceous, sparsely pubertilent on the upper surface or glabrate, short-villous beneath along 
the costa, the margins plane, the lateral veins nearly obsolete; staminate peduncles solitary, 
2.2-3 cm. long, the inflorescence capitate-corymbose, 2 cm. broad or less, the flowers on pedicels 
1 mm. long or shorter; bractlets 1-1.5 mm. long, oval, oblong, or obovate, rounded at the apex, 
