356 FLORA OF TEXAS. 



rigid; aclienia oblong, narrowed downward, 5-aiigled, 

 mostly hairy ; imppm of 5-6 ovate or triangular acuminate 

 entire membranaceous scales. — Perennial herbs^ with simple 

 and scape-like or branching stems, smooth entire 3-nerved 

 alternate leaves, and a solitary head of white or purplish 

 flowers terminating the stem or branches ; anthers blue. 



M. LANCEOLATA, Pursh. Stem naked above, simple, pu- 

 bescent; leaves lanceolate, obtuse, the lowest spatulate; 

 scales of the involucre oblong-linear, obtuse ; aclienia pu- 

 bescent. — Var., PLATYPHYLLA, Curtis. Stem leafy to the 

 middle; leaves longer and broader, the lowest (5-6') on 

 long and slender petioles. Stem 6-12' high ; leaves 2-3' 

 long. 



M. ANGUSTIFOLIA, Piirsh. stem simple or branched, 

 leafy below, puberulent above; leaves linear, acute, the 

 lowest spatulate; scales of the involucre linear and acute; 

 dislc at length ovate or oblong ; aclienia Avith hairy angles. 

 Stem 2°-3° high. 



MARUTA, Cass. May-weed. 



Heads many-flowered; the rays neutral; scales of the 

 hemispherical involucre imbricated in few rows, shorter 

 than the disk; receptacle conical, chaff'y throughout, or 

 only at the summit; aclienia obovoid, ribbed, smootli ; 

 papjjus none. — Branching annuals; leaves alternate, thrice 

 pinnately divided; heads solitary, terminal; rays while. 



M. COTULA, DC. Stern 1° high ; divisions of the leaves 

 linear ; sccdes of the involucre with scarious margins ; dish 

 yellow. 



ACHILLEA, L. Yarrow. 



Heads many-flowered, the rays pistillate, few and short ; 

 scales of the involucre imbricated; receptacle flat or elon- 

 gated, chaffy ; aclienia oblong, compressed, margined ; 



