DICOTYLEDONOUS PLANTS. 49 
and among the most specialized for insect fertilization. The 
genera of the northern United States are divided into 2 sub- 
orders: I. Tuspunirtor™, corolla of the perfect flowers 
tubular and 5-lobed; II. Licunirtorm, corollas all strap- 
shaped and flowers all perfect. 
I. TUBULIFLORZ2. 
I. ERIGERON, FLEABANE. 
Heads many-flowered, flat or nearly hemispherical, very 
many-rayed, the rays narrow, pistillate. Scales of the in- 
volucre narrow and overlapping but little. Akenes flattish, 
- erowned with a single row of hair-like bristles (Fig. 110), or 
sometimes with shorter bristles or scales outside these. Disk 
yellow, rays white, pinkish, or purple. 
a. (E. ANNUUS), ComMMOoN FLEABANE. Stem grooved and 
stout, branching, 2-5 ft. high, with scattered hairs, lowest leaves 
petioled, ovate, coarsely toothed, those higher up the stem suc- 
cessively narrower, sessile; heads in a large loose corymb; rays 
short, white or purplish. Annual or biennial. 
b. (E. strigosus), Daisy FLEABANE. Considerably resembling 
the preceding species, but with entire leaves, smaller and less 
branched stem, smaller heads, and longer rays. Annual or biennial. 
c. (E. BELLIDIFOLIUs), RoBin’s PLANTAIN. Soft-hairy; stems 
sometimes throwing out offsets from the base; simple, erect, 1-2 
ft. high ; root-leaves obovate-obtuse, somewhat serrate ; stem-leaves 
few, lance-oblong, acute, clasping ; heads rather large, 1-9, on long 
peduncles, with 50-60 long, rather broad, bluish-purple or reddish- 
purple rays. Perennial. 
d. (E. Pamapetpuicus.) Rather hairy ; stems slender, about 2 
ft. high; root-leaves spatulate and toothed; stem-leaves usually 
entire and strongly clasping, sometimes with a heart-shaped or eared 
base ; heads several, small, long-petioled ; rays exceedingly numer- 
ous, thread-like, reddish purple or flesh-color. Perennial. 
Il. ANTHEMIS, CHAMOMILE, MAYWEED. 
Heads many-flowered, with ray-flowers, rays pistillate or 
neutral. Involucre of many small, dry, close-pressed scales. 
Akenes nearly cylindrical, generally ribbed ; barely crowned 
