288 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
1. HAUYA DC. Prodr. 3: 36. 1828. 
Frutescent or arboreous; flowers large, axillary, solitary, sessile or pedunculate, 
from white to pinkish; calyx tube cylindrical, elongated, the segments narrow; 
stamens more or less exserted; filaments filiform; anthers about as long as filaments, 
awned at apex, reticulate, at length twisted; stigma globose or ellipsoidal; ovules 
most numerous, in 2 rows to the cell; capsule linear-oblong or ellipsoidal; seeds most 
numerous, biseriate, the testa coriaceous, the wing longer than the testa, unilaterally 
auriculate and incrassate; cotyledons oblong, compressed, flat; radicle very short. 
The genus Hauya wasdescribed in 1828 by A. P De Candolle in the third volume of the 
Prodromus, and a second description, probably prepared before the first, was published 
the next year. The genus contained a single species, H. elegans, based upon a drawing 
which was published along with the second description. This illustration was one 
of the few of the Mocino & Sessé drawings which De Candolle was able to reproduce, 
the others being known only from the tracings which were afterward distributed to a 
fewinstitutions. Nothing more was learned of the genus until 1877, when M. Barcena, 
a Mexican, described and figured as H. elegans a plant which he had collected in the 
State of Hidalgo. His illustration is not very good and no specimens of the plant were 
preserved. 
Mr. W. Botting Hemsley in 1878 described two additional species and in 1880 he 
amplified his descriptions and redescribed H. elegans, publishing with the text two 
plates to illustrate the three species. The first of his new species, H. barcenae, is based 
on Andrieux’s no. 391 from Oaxaca, Mexico; the second, H. cornuta, upon two speci- 
mens, one collected by Salvin and one by Savage, in Guatemala. Neither of these 
species has been re-collected. 
In 1883 Dr. Sereno Watson transferred Oenothera arborea Kellogg to Hauya, and was 
followed by Mrs. M. K. Curran, Dr. E. L. Greene, and others, but, as will be shown 
under Xylonagra, it isa very different plant from true Hauya. 
In 1893 Mr. Smith described two new species of Hauya from Guatemala and in 1898 
he assigned one of these, H. rodriguezti, to Costa Rica, publishing a new description, 
while in 1909 he and Doctor Rose described 5 new species from Central America. This 
in brief is the taxonomic history of the genus. There are a few more references to it 
in literature, but they are compiled from the papers mentioned above. 
The genus has its center of distribution in Guatemala; in fact, it is largely Guate- 
malan, for, of the 11 species described below, 7 occur in that country. One species 
is known from Costa Rica. Three species are known only from Mexico and one of the 
Guatemalan species has been found just over the border. The Mexican species are 
widely scattered, one each coming from the States of Hidalgo, Oaxaca, Guerrero, and 
Chiapas. 
This genus was named for Abbé René Just Haiiy, celebrated as a mineralogist, being 
the discoverer of the true laws of crystallization, who was in early life a student of 
botany. He was born in 1743 and died in Paris in 1822. He was a friend of the 
elder De Candolle, who published the genus Hauya six years after Haiiy’s death. 
KEY TO THE SPECIES OF HAUYA. 
Flowers distinctly peduncled. 
Peduncles much longer than the ovary.............-....... 1. H. heydeana. 
Peduncles shorter than, or at most equaling, the ovary. 
Calyx segments not appendaged........................ 2. H. barcenae. 
Calyx segments appendaged. 
Calyx segments shorter than the tube............... 3. H. lucida. 
Calyx segments longer than the tube............... 4. H. rusbyi. 
