ISANTHUS. 



LABIAT7E. 



55 



Tribe I. MENTHOIDEjE. Benth. 



Corolla somewhat campanulate or funnel-form ; the limb almost equally A: - 5-cleft : tube 

 scarcely longer than the calyx. Stamens four {or the upper pair sometimes wanting), 

 straight or diverging, nearly equal. 



1. ISANTHUS. Michx. fl. 2. p. 3 ; Benth. Lab. p. 166. false PENNYROYAL. 



[ From the Greek, isos, equal, and anthos, a flower; the corolla being nearly regular.] 



Calyx campanulate, 10-nerved, deeply 5-toothed ; the throat naked inside. Corolla about as 

 long as the calyx ; the tube straight and short : limb campanulate, of five equal obtuse 

 somewhat spreading lobes. Stamens 4, nearly equal, distant, erect, as long as the corolla : 

 cells of the anthers parallel, or at length diverging. Style 2-cleft at the summit ; the lobes 

 subulate. Achenia large, rough with little pits. — An annual, much branched, viscidly 

 pubescent herb, with few-flowered cymules and entire leaves. 



1. Isanthus c^eruleus, Michx. False Pennyroyal. 



Michx. I. c. t. 30 ; Pursh,fl. 2. p. 405 ; Muhl. cat. p. 58 ; Torr. compend. p. 233 ; Beck, 

 hot. p. 271 ; Benth. Lab. p. 167. Trichostema brachiata, Linn. sp. 2. p. 598 ; Willd. 

 sp. 3. p. 170 ; Pursh, I. c. 



Stem 8-15 inches high, obtusely 4-angled, with numerous opposite spreading branches. 

 Leaves about an inch long, elliptical-lanceolate, narrowed at each end, strongly 3-nerved. 

 Cymules numerous, axillary, on short peduncles, 1 - 3-flowered, shorter than the leaves. 

 Calyx-segments acuminate, rough and somewhat glandular. Corolla scarcely two lines long, 

 pale blue. Achenia ovoid-oblong. 



Sandy and gravelly banks of rivers ; common on the Hudson, from the Highlands upward. 

 Banks of the Erie canal between Albany and Schenectady {Dr. Knieskern) ; Jefferson county 

 (Dr. Craive). July - August. In the form of the corolla, this genus resembles Mentha ; 

 but in habit, and in the rugose-pitted achenia, it is nearly related to Trichostema of the tribe 

 Ajugoide^e. 



2. MENTHA. Dinn. ; Benth. Lab. p. 168 , Endl. gen. 3954. mist. 



From Minlhe, a daughter of Cocytus ; who, according to fable, was changed into this plant.] 



Calyx campanulate or tubular, 5-toothed, equal or somewhat 2-lipped. Corolla nearly regular, 

 4-lobed ; the broadest lobe emarginate. Stamens 4, erect, distant. Achenia smooth. — 

 Herbaceous, very odorous plants, with the cymules verticillate, capitate, or in whoiied 

 spikes. 



