ANATOMY OF TEUCRIUM NASHII. 



297 



Hypodermal coUenchymatic tissue in a single narrow layer above 

 the inidvein (as in I. optica) and several layers beneath the midvein. 



Chlorenchyma: Palisade in two layers; pneumatic tissue rather 

 open (more so than in I. aquifolium and I. opaca). 



Mestome uundleof mid vein reinforced by a narrow group of stereome 

 below the leptome, and a thinner-walled group above the hadrome.' 



Oenothera humifusa Nutt. 



Leaf densely silky-pubescent, imperfectly bifacial, midvein slightly 

 impressed above, not prominent beneath. 



Epidermis similar on both surfaces, cell walls not undulate, some- 

 what thickened, especially the outer; cuticle smooth; stomata with 

 guard cells level with the upper surface, slightly prominent beneath, 

 the majority lying parallel to the veins, but many irregular; hairs 

 densely matted, subappressed, long, sharp-pointed, unicellular, with 

 thick, granular cuticle, each radially surrounded by 5 or foot cells. 



Hypodermal collenchyma in 2 narrow layers above and 1 wide 

 layer beneath the midvein, separated from the mestome above and 

 below by colorless (water-storage?) parenchyma. 



Stereome, none. 



Chlorenchyma not sharply differentiated; palisade containing large 

 cells inclosing raphides, which are yet more abundant in the other- 

 wise rather compact pneumatic tissue. 



Teucrium nashii Kearney. 2 



Leaf normally horizontal, bifacial, dark green above, white-tomen- 

 tous beneath, margins (especially in young leaves) somewhat revolute, 

 veins impressed above, prominent and reticulated beneath. 



Epidermis: Ventral, cell walls thin, the lateral not undulate or but 

 very slightly so; cuticle smooth; stomata, none; hairs scattered, 

 mostly 3 or 4 celled, thin-walled, smooth, slender, very sharp-pointed, 

 strongly bent so as to lie nearly parallel to the surface, surrounded 

 radially by 4 to 10 (most frequently 0) foot cells. Dorsal, cell walls 

 more undulate; stomata in the sheltered interstices between the pro- 

 jecting veins, with guard cells slightly prominent, lying in all direc- 

 tions, usually bordered by 2 epidermal cells and at right angles to 

 their dividing wall, but with many exceptions; long-pointed hairs 

 forming a dense covering; also very numerous, spherical, sessile, glan- 

 dular hairs with roughened cuticle. 



Hypodermal coUenchymatic tissue in 2 or 3 narrow layers above and 



'Specimens cultivated at Washington, D. C, differ in having 3 layers of pali- 

 sade, and no stereome above the hadrome of the midvein. 



* Teucrium canadense, which is never, to my knowledge, a strand plant, differs 

 ohiefly in the less dense hairy covering of the dorsal leaf surface and in the dis- 

 tinct granular roughening of the cuticle in the pointed, as well as the glandular 

 hairs. 



