26 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE. 
and spatulate in shape. All scales thickened in the center, grad- 
ually becoming thinner toward the margin, which is scarious and 
transparent. Ligulate florets with 3 teeth at the apex, central tooth 
smaller than the other two. Calyx with fringed or slashed margin. 
Ovary possesses 5 projecting ridges. Tubular floret corolla rather 
deeply 5-toothed. Peduncle channeled and hairy. 
The Persian (186) or Caucasian insect flowers {Chrysanthemum 
roseum) differ somewhat from the Dalmatian flowers, and will be 
but briefly described. The flower heads somewhat resemble those 
of the Dalmatian variety, but are a little smaller. Ray florets, a 
reddish-purple tinge; involucral scales, dark and with reddish-brown 
edge. Fruits usually 10-ribbecr. Involucre not as hairy as that of 
the Dalmatian flower. 
SUMMARY. 
Dalmatian flowers. — Involucre: Imbricate and campanulate ; scales 
matted with hairs; individual bracts slightly thickened or keeled, the 
inner bracts becoming thinner and more chaffy or scarious at the 
margin. 
Ligulate florets: Yellowish-white or of a light straw color; pistil- 
late; apex 3 -toothed, the middle tooth usually being shorter than 
the other two. 
Disc florets: Perfect, deeply 5-toothed, and yellowish in color. 
Achenes of ligulate florets: Distinctly 5-ribbed; rather more flat- 
tened and curved than achenes of disc florets and somewhat larger; 
possess small-toothed crown. 
Achenes of disc florets: Distinctly 5-ribbed; not as curved or flat- 
tened as those of the ligulate florets; somewhat smaller; possess 
small-toothed crown. 
Persian flowers. — Involucre: Imbricate and campanulate; scales 
almost glabrous; hairs numerous in depression at juncture of peduncle 
and receptacle; scales dark and bordered by a distinctly reddish-brown 
edge; inner scales more scarious than outer ones; appear to be 
more densely fibrous than those of the Dalmatian flower. 
Ligulate florets: Tinged a rather purplish-red; pistillate; apex 3- 
toothed, middle tooth often somewhat longer than the other two. 
Disc florets: Perfect, deeply 5-toothed. 
Achenes of ligulate florets: Usually 10-ribbed; more flattened and 
curved than achenes of disc florets and somewhat larger. 
Achenes of disc florets: Usually 10-ribbed; not as curved or flat- 
tened as those of the ligulate florets; somewhat smaller. 
Microscopical Characteristics of Insect Powder. 
Before taking up the general plan followed by the authors in the 
microscopical examination of a commercial powder, the most impor- 
tant work done by other investigators will be reviewed briefly. 
