LABIATAE MINT FAMILY 
GIANT HYSSOP 
Agastache nepetoides (L.) Ktze. 
The Giant Hyssop is among our tallest common Mints, 
often 5 feet high and generally 2 feet or more. It is found in 
woods from Quebec and Vermont to Minnesota and South 
Dakota, south to Georgia and Kansas. 
In Illinois it is common throughout. 
The stem is sharply 4-angled and 
smooth or nearly so. It grows from a 
perennial underground portion and 1s 
usually branched, at least near the top. 
The leaves are similar to those shown 
except that the lower are larger and 
definitely petioled. All are ovate, smooth, 
coarsely toothed and somewhat pointed. 
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The flowers are crowded in interrupted 
terminal spikes from July to September, 
and bloom progressively upward from the 
base of the spike. The calyx is slightly 
2-lipped, the 3 teeth of the upper lip 
being slightly larger than the 2 of the 
lower lip. The corolla is greenish yellow 
and strongly 2-lipped. Its upper lip 1s 
erect and 2-lobed and the lower is spread- 
ing and 3-lobed, its middle lobe being 
much the larger and slightly uneven with 
small rounded teeth. The 4 stamens are 
attached in the throat of the corolla, the 
upper pair a little the longer. The ovary 
is deeply 4-parted and the slender style 
is 2-cleft at the end. The fruit within 
the persistent calyx consists of 4 smooth 
1-seeded nutlets. 
The Purple Giant Hyssop, Agastache scrophulariaefolia (Willd.) 
Ktze., is a yet larger plant, up to 8 feet high, and often grows along 
with the Giant Hyssop, from which it differs in little more than 
the color of its flowers, which are purple. The obtusely 4-angled stem 
and lower surfaces of the ovate or somewhat heart-shaped leaves are 
slightly soft hairy. The calyx teeth are lanceolate and acute, rather 
than ovate and obtuse as in the yellow-flowered species. 
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