IN NATURAL CLASSIFICATION. 599 
been recorded. I have endeavoured as much as possible to 
avoid errors, but in this age of inquiry, such, if they exist, 
will soon be detected; and whatever may be the result, it 
cannot but be beneficial to science. 
EXPLANATIONS OF THE DIAGRAMS. 
(Tas. XX, A). 
These diagrams are not intended to represent the appear- 
ance of the pollen in any particular species, but to show the 
combinations of characters upon which the types are founded 
that are employed for the purposes of classification in the 
subjoined memoir. 
l. The spherical, opaque, smooth pollen, dehiscing by a 
single pore, universal in Graminee and Cyperacee. 
2. The spherical pollen containing three vesicles in a com- 
mon membrane; peculiar to Juncacee ; best seen in acid. 
3. a, represents the pollen dry; 4, the same placed in water ; 
d, the same having dehisced by a broad fissure, in acid; 
this kind of pollen is present in : 
Aroidee. Amaryllidacee. 
Smilacee. Tridee. 
Colchicacee. Commelinee. 
Liliacee. Butomee. 
Asphodelee. 
4. a, represents the opaque, spherical, rough pollen, dry ; 
b, the same placed in water, and protruding vesicles on its 
surface ; e, the same placed in acid, some of the vesicles 
have dispu and one has burst, having permitted the 
fovilla to escape under the form of an opaque definite mass. 
This pollen is to be found in : 
Aristolochiee. Valerianee. 
VOL I. : 
