rp) a) Aes 
98 MISSOURI BOTANICAL GARDEN. 
tember 11,1911. The cuttings from which these plants were 
grown were collected by myself under the same number at 
Hepasote, Mexico, August 21, 1905. The description is a 
compilation of several sets of notes on the cultivated plants. 
—Plates 4 and 5. 
Opuntia vexans, sp. nov. 
An arborescent, cylindrical-jointed species with the habit of 
O. arborescens and about equal to that species in stature, reaching in 
rare instances a height of 3 meters and having a spread of about the 
same diameter; joints cylindrical, usually more or less curved, some- 
what clavate when young on account of the gradual narrowing toward 
the base, varying in length from 10 to 40 cm., and 2 to 3 cm. in 
diameter, tuberculate, the tubercles about 5 mm. high and normally 
83cm. long, the upper crest abrupt and less than one-third the entire 
length, the highest point being at the upper extremity of the areole, 
the lower slope twice as long or longer and gradual; areoles oval, gray, 
acutely angled above, 6 to 7 mm. long, enlarging by formation of new 
structures above, and becoming sub-circular or obovate and 6 mm, or 
more in diameter, forming mostly a flat cushion 1 to 2 mm. high, at 
2or 3 years of age; spicules yellow, in a small triangular tuft less 
than 1 mm. long in upper part of areole, not increasing in age; leaves 
long, cylindrical, subulate, cuspidate-pointed, 1.5 em. long, usually 
tinged at tip; spines reddish-brown, with rather close, gray to silvery 
sheaths, variable, 4 to 10 on current year’s joints, increasing to 30 or 
more in age, erect, diverging in all directions, commonly 4 to 10 mm. 
long; flowers delicate light purple, 514 to 7 cm. in diameter when 
fully opened, inner row of petals 8, obovate-spatulate, rounded to 
retuse and minutely cuspidate above, filaments greenish purple, more 
deeply colored distally, style purple, fading below to almost white, 
stigma white, 7 to 8-parted; fruit dry, obovate, tubercled at first, 
becoming less so in age but never smooth, greenish yellow when ripe, 
drying upon the plant and then falling off, obovate, 22 X 35 mm. or 
subglobose and 22 25 mm., armed with the usual bunch of spicules, 
and 1 to 8 or 4 delicate, fugacious, hairlike spines sheathed at their 
tips only. 
The species belongs to the O. arborescens group and 
is commonly confused with that species, from which it dif- 
fers in the character of its fruits and tubercles especially, 
and agrees with it in form and grosser aspects. It is one of 
the best ornamental species of the group and is readily propa- 
gated from cuttings and less so from seed. At Chico, Cali- 
fornia, it makes two crops of fruit usually, and at San An- 
