BULLETIN 795, U. S. DEPARTMENT OF AGRICULTURE. 
The achenes of Chrysanthemum drier arias folium and Chrysanthe- 
mum leucantherrmm are strikingly different in the powdered form. 
The achene tissues of the Dalmatian flowers (C. cinerar/afolhi.m) 
are characterized by numerous crystals. On the other hand, the 
achene tissues of the daisy flowers (C. Itucanthemum) exhibit no 
such crystals, but contain a notable quantity of a brownish-red mate- 
rial, the location of which is readily demonstrated in a cross section 
of the fruit. In a cross section of the achene, crescent-shaped struc- 
tures, corresponding to each of the 10 ribs, stand out very distinctly 
(Fig.'l). 
"W hen the daisy flower heads are powdered, this brownish-red ma- 
terial contained in the crescent-shaped structures breaks up into 
irregular, angular fragments, sometimes attached to the surrounding 
tissues and sometimes separated from them. These fragments have 
a deep, brownish-red color 
and are clearly seen when 
the powder is warmed in 
a solution of chloral hy- 
drate in water ( about 
1:1). 
Another diagnostic 
element is a portion of 
the tissue from the white 
ribs of the daisy achene. 
The outer portion of the 
rib consists, in radial sec- 
tion, of what are appar- 
ently e p i d e r m a 1 cells. 
They appear to have a 
palisadelike arrangement, 
consisting of narrow, 
thick-walled cells packed 
very closely together (PL 
II, Fig. 2). This tissue. 
which invariably occurs 
in the daisy powder in the 
form of radial sections, serves as another means for detecting its 
presence in genuine insect powder. 
Experience gained in the comparative study of a large number of 
samples ground from insect flowers and from daisy flowers has 
emphasized the need for caution in placing reliance upon any histo- 
logical characters in the daisy flowers other than those of the achene. 
Other characters, with the exception of the T-shaped hairs of the 
Dalmatian flowers (PL II. Fig. 3) and the crystal-bearing -tone cells 
of the achene. are too nearly like similar characters in insect flowers. 
While these hairs and crystal-bearing stone cells of the achene would 
furnish a means of identifying Dalmatian flowers in a mixture with 
other materials, they apparently offer no means of disclosing the 
presence of the daisv flowers when mixed with Dalmatian flowers 
Thus the presence of this brownish-red material (PL I. Fig. 4-) and 
the palisadelike epidermal cells (PL II. Fig. 2) furnish a reliable 
means of detecting even small quantities of daisy flowers in a mixture. 
Fig. 1. — Cross-section of daisy achene lillustiatin 
cieseent-shaped structures.) 
I 
