1887. | BOTANICAL GAZETTE, 267 
open, during the night. Such is the perfume of the tuberose, 
jessamine, white lily (L. candidum), night-blooming cereus 
and many others. Delightful as it is, its physiological effect 
is undesirable. It enervates the system, and sometimes even 
causes headache. Opposed to this is the bracing odor of the 
hop, found also in hemp, although in a less pleasant combi- 
nation. The hop aroma restores the balance of the nervous 
system, allays headache, and promotes a healthy, refreshing 
sleep. The absinthine odor of wormwood, chamomile, chrys- 
anthemum and many other plants stimulates the skin to 
healthy action, relieves fever and promotes perspiration. 
nd now, to test the practical value of the theory, take a 
plant, hitherto unknown, with a labiate corolla and didyna- 
mous stamens. Its appearance indicates that it may belong 
mistake peppermint for spearmint, much less for thyme, sage, 
Catnip or lavender. Then, are the other orders mentioned de- 
void of odorous species? Linaria is decidedly odorous, though 
by no means fragrant; Veronica, in some of its species, has 
a faint but agreeable smell, and Lippia citriodora a delightful 
fragrance. What common element is there, then, in the vari- 
ous odors of the Labiatz by which the species of that order 
may be generally identified? The epithet ‘* aromatic, 
This peculiar sensation is the effect of an odor common to all 
the Labiata. I have noticed it in Monarda fistulosa, a plant 
_ With a smell distinct from that of mint, owing to the pres- 
ence of a citric element which mint lacks. I have detected 
it beneath the honeyed sweetness of thyme and lavender, as 
Well as under the absinthine element in sage, and the scarcely 
agreeable geranium element in ground ivy. In some of the 
