239 
1. L. Newberryi Gray. Leaves 2 to 3-pinnately parted into filiform-linear seg- 
ments: heads few or several at the naked summit of the stem: rays 18 mm. long, ob- 
scurely 3-lobed, at first yellow, soon changing to cream-color or white: achenes 
turning black.—Guadalupe Mountains, extreme southwestern Texas (Havard). 
102. ANTHEMIS L. (CHAMOMILE. ) 
Branching strong-scented herbs, with finely pinnately dissected 
leaves, solitary terminal many-flowered heads with white rays and yel- 
low disk, numerous small imbricated dry and scarious involucral scales, 
conical receptacle with slender chaff at least near the summit, terete or 
ribbed glabrous truncate achenes, and pappus none or a minute crown. 
1. A. Cotula DC. (May-weeEp.) Acrid annual: leaves finely 3-pinnately dissected: 
rays mostly neutral: receptacle without chaff near the margin: pappus none. (Maruta 
Cotula DC.)—A very common weed, introduced from Europe. Known in many 
places as ‘‘ dog-fennel.” 
103. ACHILLEA Vaill. (Yarrow.) 
Perennial herbs, with small corymbose many-flowered radiate heads, 
few and fertile rays, imbricated involucral bracts with scarious mar- 
gins, chatty flattish receptacle, oblong flattened margined achenes, 
and no pappus. 
1. A. Millefolium L. Stems simple: leaves twice-pinnately parted; the divisions 
linear, 3 to 5-cleft, crowded: corymb compound, flat-topped: rays 4 or 5, short and 
white (sometimes rose-color).—-Commonly introduced throughout all North America. 
Known both as “milfoil” and “ yarrow.” 
104. MATRICARIA Tourn. (WILD CHAMOMILE.) 
Smooth and branching herbs, with finely divided leaves, single or 
corymbed many-flowered heads, pistillate rays or none, imbricated invo- 
lucral bracts with scarious margins, conical naked receptacle, 3 to 5- 
ribbed wingless achenes, and pappus a membranaceous crown or bor- 
der or none. 
1. M. Chamomila L. Aromatic annual, resembling ‘‘mayweed”: heads 6 mm. 
high and rays as long: involucral bracts oblong and fuscous: achenes with an ob- 
scure border and usually no distinct pappus.—Introduced in some of the Atlantic 
States, but represented in cultivated fields of central and southern Texas by var. 
CORONATA Gray, in which the ray achenes and mostly those of the disk are fur- 
nished with a conspicuous thin scarious cleft and toothed (sometimes unilateral) 
pappus. 
105. ARTEMISIA L. (WorMwoop. SaGE-BRUSH. MUGWORT.) 
Bitter and aromatic herbs or shrubby plants, with small commonly 
nodding discoid heads in panicled spikes or racemes, small and flattish 
naked receptacle, obovoid achenes with a small summit, and no pap- 
pus. 
* Receptacle smooth: marginal flowers pistillate and fertile: disk-flowers perfect but sterile. 
+ Leaves dissected or divided. 
1, A. caudata Michx. Smooth, 6 to 15 dm. high: upper leaves pinnately, the 
lower 2 to 3-pinnately divided, the divisions filiform and diverging: heads small, 
the racemes in a wand-like elongated panicle..-Sandy ground, near the coast. 
