Asclepias subverticillata (A.Gray) Vail

178	Vail: Studies in the Asclepiadaceae
4. Asclepias subverticillata
(A. Gray).^^/
Asclepias verticillata, var. galioides Torr. Mex. Bound. Surv.	'
164. 1859. In part.
Asclepias verticillata, var. subverticillata A. Gray, Proc. Am.
Acad. 12: 71. 1876. In part.
Glabrous except the minutely pubescent stems and pedicels.
Stems slender, erect, 2-3 dm. high, from a slender vertical root-
stock, simple or branched ; internodes at the base of the stems
5-10 cm. long ; leaf-scars remaining conspicuous : leaves crowded, *
opposite above, otherwise verticillate in threes or fours; blac[£^k,.
narrowly linear, 4—10 cm. long, 1—2 mm. wide, acute at eacl end^
coriaceous, with a whitish midvein : umbels 4—8, lateral an( ter-
minal, 2-2.5 cm. in diameter, corymbosely disposed at or nes r tfcfe
summit of the stem, commonly many-flowered : peduncles k nger
than the minutely pubescent pedicels and considerably shorter than
the upper often elongated leaves : corolla-segments greenish-white"
4-5 mm. long, obtuse or acutish : column nearly 1 mm. high :
hoods erect-spreading, nearly as high as the anthers, dorsally has-
tate-sagittate at the base, broadly rounded at the summit, the ven-
tral margins rounded, not angled at the slightly involute middle :
anther-wings narrow, very slender, prominently sagittate at the
minutely notched base : follicles 8 cm. long, slender, long-acumi-
nate, minutely puberulous : seeds about 4 mm. long ; coma 2 cm.
long. Mature fruit not seen.
New Mexico: Wright, no. 1686, 1851-52, in Herb. Columbia
University. Western Texas : Wright, “ mountain valley beyond the
Limpia, Aug. 26th,” no. 550, and “valley, 20 miles beyond the
Pecos, Aug. 17,” no. 551, 1849 Herb. Gray. Arizona: Fort
Verde, E. A. Mearns, no. 235, in Herb. Columbia University.
Asclepias verticillata, var. subverticillata was established by Dr.
Gray, based “ chiefly ” on Asclepias verticillata, var .galioides Torrey
(Mex. Bound. Surv. 164. 1859). In that publication Dr. Torrey
bases his variety on a specimen of Parry’s from Sonora and New
Mexicoj and on three numbers of Charles Wright’s collection of
1851—52, nos. 1685, 1686 and 1689, adding that “ our plant seems
to be the same as Hartweg’s no. 216.” Specimens of these last-
mentioned numbers are preserved in the Herbaria of Columbia
University, Harvard University, and the U. S. Nat. Museum. I
am not sure that I have seen Party’s specimen, which, according
to the copy of the Report of the Mexican Boundary Survey an-
notated^B^CrT*Torrey, should be numbered 1078a. A specT^
men from this collection in the Herbarium of the U. S. Nat.
Museum answers the description very well, but lacks any kind 01
a number so I do not like to refer to it with certainty. The first
number of Wright’s (1685), is undoubtedly the same as Hartweg’s
plant and is A. galioides, H.B.K.; but the no. 1686 seems to show
a marked variation which is rather striking. The same plant
occurs is Wright’s Western Texas collection and more recently
has been found at Fort Verde, Arizona.
A low (2—3 dm. high), slender plant, with remarkably crowded,
long, narrowly linear leaves which are verticillate in fours or the
uppermost in twos or threes. The internodes at the base of the
stem are only from 6—10 mm. long and the leaf-scars are con-
spicuous, a character which I have not noticed on any other forms.
I have little doubt but that this is a good species and give it the
vari	„
Examined by Anna Murray Vail.
HUM
1VERS1TY,
-*ORK.
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