STANDLEY— ALLIONIACEAE OF MEXICO. 385 



2. TORBUBIA Veil. 



Torrubia Veil. Fl. Flum. 139. 1825. 



Type species, Torrubia opposita Veil. 



The genus is represented in the West Indies by a number of species. Representa- 

 tives are found in various parts of South America as well. Hemsley did not recognize 

 Torrubia as distinct from Pisonia, but he cited Pisonia pacurero, properly a member 

 of this genus, from Guatemala. That species is a Venezuelan one and the writer has 

 seen no Central American material that could be referred to it. 



1. Torrubia costaricana Standley, sp. nov. 



A small tree; twigs slender, greenish gray, smooth and glabrous; leaf blades ellip- 

 tic or narrowly oblanceolate, 80 to 110 mm. long and 20 to 34 mm. wide, dull green, 

 glabrous, long-acuminate at the apex, tapering at the base to a slender petiole 5 to 10 

 mm. long; staminate inflorescence rather densely corymbose, 25 to 35 mm. wide, on a 

 slender, almost glabrous peduncle 25 to 30 mm. long; perianth narrowly campanulate, 

 2 mm. long, almost glabrous, on a stout, puberulent pedicel; stamens 5, twice as long 

 as the perianth; pistillate inflorescence and fruit not seen. 



Type in the herbarium of Capt. John Donnell Smith, collected in the forests about 

 Nicoya, Costa Rica, in May, 1900, by A. Tonduz (no. 13927). The collector states 

 that the perianth is white and that the flowers are fragrant. The species is related to 

 Torrubia inermis, but the very different leaves alone are sufficient to distinguish it. 



3. PISONIELLA Standley, gen. nov. 



Pisonia section Pisoniella Heimerl, in Engl. & Prantl, Pflanzenfam. 3 1 *: 29. 1889. 



Low shrubs with numerous forking or rarely opposite branches; leaves entire, 

 petioled, opposite; inflorescence of numerous axillary, long-peduncled, many- 

 flowered umbels; flowers hermaphrodite, narrowly campanulate; stamens 6 to 8, 

 exserted; style depressed -capitate ; perianth enlarging in age and becoming hardened 

 and leathery, inclosing the fruit, becoming 5-angled and producing from each angle 

 a row of papillose, viscous glands. 



Type species, Boerhaavia arborescens Lag. 



Although originally described as a species of Boerhaavia the type of the genus has 

 usually been placed in the genus Pisonia, to which it is more closely related . The fruit 

 is very similar to that of Pisonia, but the inflorescence, the style, and the habit of the 

 plant are very different. Several times the type species has been described under 

 the genus Boerhaavia. It does possess certain relationships with Commicarpus scan- 

 dens, that being, no doubt, of the group to which it was referred. The fruit, however, 

 is such as to exclude the plant from the genus Commicarpus. Unfortunately it has 

 been impossible to get mature fruit of either species to determine the form of the 

 embryo. It is to be expected that it will be straight or but slightly curved as in the 

 species of Pisonia. 



KEY TO THE SPECIES. 



Stems and leaves puberulent and more or less glandular; leaf 



blades short-acuminate, rounded at the base or subcordate. . LP. arborescens. 



Stems and leaves glabrous; leaf blades long-acuminate, attenuate 



or acuminate at the base. (South America.) P. glabrata. 



1. Pisoniella arborescens (Lag. & Rodr.) Standley. 



Boerhaavia arborescens Lag. & Rodr. Ann. Cienc. Nat. 4: 257. 1801. 

 Pisonia hirtella H. B. K. Nov. Gen. & Sp. 2: 217. 1817. 

 Boerhaavia octandra S. "Wats. Proc. Amer. Acad. 26: 145. 1891. 

 Type locality, "Salvatierra," Guanajuato, Mexico. 



