THISTLE FAMILY 689 
tile or not. Disk flowers with stamens and pistils, fertile. Anthers ob- 
tuse, without appendages at base. Aigrette none. - 
1. A. Cotula, L: (Fig. 2, pl. 193.) Maywrep. Stems much 
branched, erect or semi-prostrate, 1 io 2 ft. high, the plant with an un- 
pleasant odor. Leaves finely dissected into thread-like segments. Heads 
numerous, about 1 in. broad; rays 10 to 18, white, disk light yellow. Com- 
mon in waste places. June-Nov. 
2. A.arvensis, L. Firtp Camomite. Leaves less finely dissected; 
rays 10 to 18, longer than those of the Mayweed. Introduced, in waste 
places. May-Aug. 
3. A. tinctoria, L. YeELLow CamomiLe, Leaves with feather-form 
divisions, the segments toothed. Heads 1 to 13 in. broad; rays 20 to 30, 
yellow. Introduced, waste places. June-Sept. 
39. CHRYSANTHEMUM, L. 
Perennial herbs with more or less divided leaves and with solitary or 
clustered heads of tubular and ray flowers on long slender stems. Invo- 
lucre bracts of several series; receptacle flat without chaff. Rays white, 
tubular florets yellow. Anthers obtuse without appendages. 
C. Leucanthemum, L. (Fig. 5, pl. 193.) Wuuite WEED. OX-EYE 
Daisy. Root perennial. Stem simple or branching, 1 to 3 ft. high. Leaves 
of the upper part of the stem without leaf-stalks, those below with long 
leaf-stalks, the blades deeply incised or conspicuously toothed. Heads soli- 
tary or few, 1 to 2 in. broad. Rays 20 to 30, white, disk yellow. The 
too-common daisy of meadows and pastures. May-Noy. 
40. MATRICARIA, L. 
Smooth branching herbs with alternate dissected leaves and heads on 
long stems with tubular and ray flowers, or rays sometimes wanting. 
Involucre scales overlapping, with dry borders; receptacle conical, free 
from chaff; rays white, bearing pistils and producing fruit; disk florets 
fertile. Anthers without appendages. 
1. M. inodora, L. Scentress Camomite. Annual; leaves dissected 
into almost thread-like segments. Heads large, 4 to 14 in. broad; rays 
20 to 30, white. Aigrette a short border. Wild in northern part of our 
area. June-Sept. 
2. M. suaveolens, (Pursh.) Buchenan. Rayrtess CAMomILE. (M. 
matricarioides, (Lees.) Porter.) Smooth, 4 to 14 ft. high. Leaves dis- 
sected. Heads numerous; rays wanting; disk conic, yellow. Waste places, 
introduced from the Pacific Coast. May-Aug. 
41. TANACETUM, L. 
Strongly aromatic herbs with alternate, dissected leaves and many heads 
of tubular flowers or with, in exceptional cases, not fully developed, a 
few ray flowers. Involucre of small overlapping scales; receptacle con- 
vex, naked; florets at the margin of the disk bearing pistils only; those 
