THE MINT FAMILY. 215 



XXXV. THE MINT FAMILY. LABIATJE. 



MATERIAL REQUIRED. 



Specimens of ground-ivy, Nepeta Glechoma, Benth., in flower. 

 Similar specimens belonging to different genera of the Mint family, 

 as they can be obtained. See list below. 



GROUND-IVY. Nepeta Glechoma, Benth. 

 Distribution. 



As in previous studies, notice the habitat and consider 

 the evidence as to whether this is an introduced or indige- 

 nous species. Gray, in the Manual, says "naturalized 

 from Europe." What is meant by this? 



General Characters. 



I. Observe first the most obvious characters, among 

 them the following: 



1. The habit of the plant, its stem creeping and taking 



root at short intervals. Describe the root system. 



2. The characteristic odor. 



3. The shape of the stem and arrangement of the 



leaves. 



NOTE. The aromatic properties, square stem, and opposite 

 leaves are characteristic not only of this species but of the whole 

 family to which it belongs. 



4. The relation of leaves and stem. Note particularly 



the ridges connecting the bases of each pair of 

 petioles, and their chevaux-de-frise of bristly 



