IN NATURAL CLASSIFICATION. 595 
ledons with many ovules, afford us important evidence of 
affinity derivable from the pollen. In both these families, 
this organ is compounded of three or four vesicles, connected 
by threads. 
It is amongst polypetalous dicotyledons, that the pollen 
possesses the most remarkable taxonomic importance. Thus, 
Umbellifere is as certainly distinguished by the nature of its 
pollen as by any combination of other characters. It is no- 
torious, that the characters which are most valuable for sub- 
dividing other divisions of the vegetable kingdom, are 
amongst the Polypetale, very ineffectual, and I am of opi- 
nion that the pollen might be most advantageously employed 
to supply this defect. 
Thus, the nature of the pollen in Onagrariacee is of greater 
consequence than the attachment of the seeds, or the number 
of the ovules ; inasmuch as this family is separated by these 
latter characters from Circee, with which it is otherwise 
closely connected, while the pollen is the same in both. 
Again, the characters that separate Onagrariacee from Circee, 
unite it with Myrtacee and Lythrariee, with whom its affi- 
nities are comparatively obscure ; but the nature of the pollen 
distinguishes it from these families. 
Leguminose is connected by its perigynous exsertion, ex- 
albuminous seeds, parietal placente, and numerous ovules, 
with Cucurbitacee, Cactacee and Mohringee, with which the 
details of its organization present little in common; while it 
is separated by some of these characters from Rosacee, with 
which it is so closely allied ; the nature of its pollen, how- 
ever, at once separates it iuis the former families, and unites 
it with the latter. 
The pollen is frequently of more — amongst po- 
lypetalous plants than the albumen. Thus, Crucifere, Cap- 
paridee and Resedacee are strictly allied to Papaveracee, 
Fumariacee, Violacee, &c., but are separated by the absence 
of albumen; the pollen reunites them. And, again, the al- 
buminous order Crassulacee is more closely connected by its 
general characters with Zosacee, through Sawifragee, than 
