126 
.1. A. acaulis. Cespitose, with peduncles 4 to 10 inches 
high, often much longer than the leaves: leaflets ovate, irregularly 
toothed and cut, sometimes almost pinnatifid: umbel 8 to 15-raved; 
rays 5 to 10 lines long; fruit almost sessile, 1^ lines long, (Fig, 
147.) — Dezveya (?) acaulis Torrey, Pacif. R. Rep. iv. 04. Oreos- 
ciadium acaule Gray, Proc. Am. i\cad. vii. 843. Seseli Hallii 
Gray, 1. c. viii. 288. Musenium Greenei Gray, 1. c. 887. Cartini 
(?) Hallii Watson, Bibl. Index. Polypet. 416. Zizia Hallii 
C. & R. Bot. Gazette, xii. 187, foot-note. 
In the foot-hills of Colorado and Now Mexico. FI. May. 
The history of this species has been somewhat remarkable. Not only has 
it been referred to six genera, but it has stood under three of them at the 
same time. Eeferred first doubtfuliy to Deweiia by Torrey in 1850, it was 
transferred by Gray to Oreosciadium in 1808. It then turned up in the Hall 
ifc Harbour collection and was described as Seseli Hallii Grav in 1870. A 
year or two later it was sent to Dr. Gray by E, L. Greene, and appeared in 
1872 as a new species of Musenium, M. Greenei Gray. At this time the 
same plant was appearing in our publications under three names, Oreos- 
ciadium acaule, Seseli Hallii, and Musenmm Greenei, all of Gray. In his 
Bibliographical Index, Watson referred it doubtfully to Carum, as C. (?) 
Hallii, at the same time recognizing the identity of Seseli Hallii and 
Musenmm Greenei, and quoting them as synonyms. In 1887, however, in 
Proc. Am. Acad. xxii. 475, Watson records the identity of Oreosciadium 
acaule with his Carum (?) Hallii, and so the names were at last reduced to 
one. The fruit characters are those of Zizia, and if they are to dominate 
over every other consideration this piant must be a Zizia, as we suggested 
in Bot. Gazette, xii. li>7. But no character should be used too arbitrarily, 
and the complete disimilarity of habit between the recognized species ot 
Zizia and this species seems something that cannot be neglected. If such 
a thing is to be neglected in this ease, consistency would demand a con- 
• solidation of genera such as we are not at present disposed to accept. 
If this plant, then, is not a Zizia, nor any of the numerous genera pro- 
posed for it, a genus must be made for it, for surely, if a plant 
does not satisfy any genus, it must be sui generis. That it does 
not satisfy the demands of any recognized genus is to be inferred 
from its strange history; but it maj^ be proper to point out a few of the 
reasons why it cannot belong to any of the genera heretofore proposed for 
it. It is hardly necessary to show why it cannot be a Vehna (Detceya). 
From Oreosciadium it differs in its prominent calyx-teeth, pinnate leaves, 
and yellow flowers; from Seseli in its laterally flattened fruit, yellow flow- 
ers, and whole habit; from Musenium in its much more prominent ribs, 
strengthening cells, solitary oil- tubes, almost plane seed- face, and simpler 
leaves; from Ceirum in its depressed stylopodium, yellow flowers, and its 
general habit. Taking its habit and fruit both into consideration it is more 
nearly related to Musenium than any other genus. For the reasons given. 
