DIDYNAMIA. GYMNOSPERMIA. 97 
A genus of about 25 species almost exclusively Euro- - 
pean, yet extending to India and the Cape of Good Hope. 
397. ISANTHUS. Michaux. 
Calix subcampanulate. Corolla 5-parted; 
tube straight and narrow; segments of the bor- 
der ovate and equal, Stamina subequal. Stig- 
mas linear, recurved. 
‘Annual, covered with a viscid pubescence, leaves en- 
tire, longitudinally nerved, flowers axillary and peduncu- 
late, greyish-blue, calix becoming zruginous. : 
Species. 1. T.ceruleus.  Trichostema brachiata. L. 
Has. In Pennsylvania, Maryland and Virginia, but more 
abundant west. of the mountains, from whence it appears 
to have originally propagated along the Ohio and the Mis- 
sissippi as well as part of the Missouri—The only spe- 
cies. Seeds reticulately rugose as in T'richostema to 
which this genus is somewhat allied. 
398. HYSSOPUS. L. (Hysop.) 
Lower lip of the Corolla 3-parted, interme- 
diate segment subcrenate. Stamina straight, 
and distant. 7 oe git 
A very unnatural genus of about 3 or 6 species; flowers 
in H. officinalis axillary and verticillate; corolla in H. Lo- 
phanthus resupinate with the flowers partly cymose; the 
American species scarcely distinct from Wepeta, are tall 
plants with cordate-ovate toothed leaves, and dense ter- 
minal verticillated spikes, with white or pale blue flowers. 
Species. 1. HM. sepetoides. Bractes dilated; calix 
smooth, segments linear. 2, scrophulariefolius, Bractes 
ovate acute; calix smooth, segments subovate. 3. * ani- 
satus. Smooth; spikes verticillate interrupted; leaves cor- 
_ date-ovate, angularly toothed, under side glaucous; ¢alix 
.» . siequal, acute, pubescent, segments subovate, about one third 
s the length of the calix; bractes scarcely as long as the pe- 
dicells. Stachys Feniculum, Pu. Has. On the plains of 
the Missouri near Fort Mandan, on the borders of thick- 
arets, 
4 
