198 COMPOSITE. (composite family.) 



pinnately parted into 7 to 9 linear-filiform pointless divisions : involucre 3 lines 

 high : rays about 12, oblong, 3 lines long : pappus of 6 or 8 quadrate or oblonfi 

 and erose-truncate scales, in length little exceeding the breadth of the akeno 

 — Proc. Am. Acad. xix. 42. Plains of Colorado to W. Texas. 



O. PECTIS, L. 



Mostly low and spreading herbs, usually glabrous and scented ; with narrow 

 opposite leaves conspicuously dotted with round oil-glands; small heads of 

 yellow flowers ; and slender rigid bristles fringing at least the base of the 

 leaves. 



1. P. angustifolia, Torr. A span or two high, lemon-scented: leaves 

 narrow-linear : heads subsessile or short-peduncled, fastigiate or cymose at 

 the end of the branches : bracts of the involucre about 8, linear, at length 

 with involute margins : pappus a crown of 4 or 5 mostly connate scales, and 

 not rarely one or two slender usually short awns. — Ann. Lye. N. Y. ii. 214. 

 Dry ground, Colorado and Arizona to Texas. 



61. LEUCAMPYX, Gray. 



Named from the circle of bracts of the head being white-bordered. 



1. L. Mewberryi, Gray. Perennial herb, a foot or two high, flocculent- 

 woolly, glabrate in age : leaves 2 to 3-pinnately parted into filiform-linear seg- 

 ments : heads few or several at the naked summit of the stem : involucre 

 nearly £ inch broad : rays f inch long, obscurely 3-lobed at summit, at first 

 yellow, soon changing to cream-color or white : akenes 2 lines long, turning 

 black. — Fl. Colorado, 77. S. W. Colorado, and W. New Mexico. 



62. ACHILLEA, 1 Vaill. Yarrow. 



Herbs ; with small and corymbosely cymose heads of white, yellow, or even 

 rose-colored flowers ; disk commonly yellow. 



1. A. Millefolium, L. From villous-lanate to glabrate: stems simple, 

 a foot or two high : leaves elongated and narrow in outline, sessile, bipinnately 

 dissected into numerous small and linear to setaceous-subulate divisions : 

 heads numerous, crowded in a fastigiate cyme : involucre oblong ; its bracts 

 pale or sometimes fuscous-margined, or even wholly brownish : rays 4 or 5, 

 about the length of the involucre, white, occasionally rose-color. — Common 

 throughout the Northern hemisphere. Called either " Yarrow " or " Milfoil." 

 Exceedingly variable. 



1 The Old-World genus Anthemis has several species naturalized in this country, one of 

 which is an excessively common weed at the East, and becoming abundant within our range. 

 It may be characterized as follows : — 



A. Cotula, L. Stem rather low : herbage unpleasantly strong-scented : leaves finely 

 3-pinnately dissected : receptacle conical : rays mostly neutral and white or abortive : akenes 

 10-ribbed, rugose or tuberculate. — Known as "Mayweed" or "Dog-Fennet" Marvin 

 Cotula, DC. 



