Agastache cusickii (Greenman) A. A. Heller 

 Cusick's Horse-mint 



A. DESCRIPTION 



1. General description: A. cusickii is an aromatic 

 perennial in the mint family (Lamiaceae). Its habit, low 

 growing from a long, flexible, branching woody caudex, is 

 adapted to growing in deep, loose talus. The small 

 simple leaves are diamond to egg shaped with serrated 

 margins and short petioles and are borne opposite each 

 other on relatively short aerial stems which are square 

 in cross section. The small flowers are borne in a dense 

 spike-like inflorescence with leaf like bracts. The 

 flowers are bilaterally symmetrical with a fused 5- 

 toothed calyx and a tubular, 2-lipped, usually lavender 

 corolla. There are 4 exerted stamens and a single pistil 

 with a bilobed stigma. Figure 3 is an illustration of 

 the species, and photographic slides of the plants are 

 attached at the end of this report. 



2. Technical species description (quoted from Cronquist et 

 al . 1984): Stems numerous from a woody taproot and 

 branching caudex, 1-2(3) dm tall, simple or branched, 

 tending to be somewhat woody at the base; stem, leaves, 

 bracts, and calyces finely hirtellous-puberlent ; leaf 

 blades ovate, deltoid-ovate, or a little narrower, 

 crenate, mostly (0.5)1-2(2.5) cm long and (4)6-15 mm 

 wide, borne on petioles up to 1(1.5) cm long; 

 inflorescence mostly (1)1.5-4 cm long (exclusive of any 

 remote verticillasters ) , the bracts and calyces usually 

 tinted with lavender-purple (seldom whitish in part); 

 calyx teeth 2-5 mm long, lance-subulate, obscurely 

 veined, or only the midrib evident, seldom more evidently 

 tri-nerved; corolla 8-12 mm, measured to the tip of the 

 upper lip, this 1-2 mm long and evidently bilobed; lower 

 pair of stamens ascending under the upper lip and exerted 

 1-2 mm past it; upper stamens thrust downward and outward 

 between the lower stamens, exerted 2-5 mm. 



3. Diagnostic characters: In Montana, Agastache 

 urticifolia, common horsemint, is the only other species 

 in the genus. The two taxa are easily distinguished 

 based on their overall size; A. cusickii is dwarf (1-3 dm 

 high) with smaller leaves (1-2.5 cm), while A. 

 urticifolia is large and coarse (>4 dm) with larger 

 leaves (3.5-10 cm) (Hitchcock and Cronquist 1973). 



