THE ALLIONTACEAE OF THE UNITED STATES, WITH 
NOTES ON MEXICAN SPECIES. 
By Taunt (. STANDLEY, 
INTRODUCTION. 
Of all the families of North American plants none, probably, have 
been more neglected than the Allioniaceae. In the last fifty-five vears 
no monograph of the American representatives of the family has ap- 
peared, Linneus in the Species Plantarum published two North 
American genera of this family—Mirabilis, with one species, and 
Boerhaavia with four species, only two of which, however, occur in 
the region under consideration. Other genera and species of the 
family were soon published, all of them in scattered publications. 
The first treatment of the family as a whole was that of Choisy in 
De Candolle’s Prodromus. In that work, 10 North American genera 
were described and, under them, 31 species, not including several 
species of Pisonia. Choisy’s work is interesting and at times help- 
ful, but the author labored under the difficulty of not having seen 
some of the plants of which he wrote, as a result of which some seri- 
ous mistakes were made. The next work of any importance dealing 
with the family was that of Asa Gray, in the Botany of the Mexican 
Boundary Survey;¢ that paper is a very brief one and includes de- 
scriptions of but few species, although Gray described at various 
times a considerable number of new genera and species in the Al- 
lioniaceae, 
Dr. Anton Heimerl, of Vienna, probably the foremost student of 
this group of plants, contributed to Engler and Prantl’s Natiirlichen 
Pflanzen-Familien ’ the section dealing with the Allioniaceae, a paper 
valuable for the excellent discussion it contains of the various genera. 
The work is exceedingly conservative, and the family is treated as 
1859. (Emory, Rep. U. S. 
#4, Gray in Torrey, Bot. Mex. Bound. 172-175. 
& Mex. Bound. Surv. Vol. II, Pt. 1.) 
b Teil III, Abt. 1 b, pp. 14-82. 1889. 
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