498 BOTANICAL SURVEY OF DISMAL SWAMP REGION. 



of the one-celled hair is filled with protoplasm, which contains a pretty large cell 

 nucleus in the base of the hair. In a hair which has developed somewhat farther 

 one finds that the wall of the hair has become somewhat thicker, and that the 

 protoplasm which originally filled both the base of the cell and the channel of 

 the hair has altogether withdrawn to the base of the cell and has completely left 

 the channel; the protoplasm now fills only the base of the cell and deposits on the 

 side which faces the channel of the hair a membrane which in the particular plant 

 in which its development was studied increases considerably in thickness. In 

 other species, as will be shown, this membrane, which is thrown off by the proto- 

 plasm (on the side) facing the apex of the hair, remains relatively thin. 



•■ No nuclear division, therefore, occurs in this hair cell: in these Combretaceous 

 hairs, as has already been said, we have to do with truo one-celled trichomes." 



I Ielianthemum canadense (L.) Michx. 



In open pine woods near the strand. 



Leaf bifacial, pubescent, especially beneath. 



Epidermis: Cells with thin walls, the radial somewhat, undulate. 

 Hairs on both surfaces of three types: (1) Plurieellular, scale-like, 

 stellate hairs with .'1 to K slender, sharp-pointed arms that are parallel 

 to the leaf surface, each hair bordered by several radially arranged 

 foot cells; (2) long;, stout, very thick-walled falsely bicellular hairs of 

 the peculiar cistaceous type described under LecJiea marUima, and 

 (3) rather few multicellular, glandular hairs. Stomata only on I he 

 dorsal surface, numerous, mostly parallel to the longer axis of the 

 leaf, level with the surface. 



Palisade compact; pneumatic tissue rather open. 



Hypodermal cottenchyma strongly developed above and below the 

 larger veins. 



Nyssa aquatioa L. 



(Nyssa uniflora Wang.) 



Ilygrophile Forest formal ion. 



Leaf large, thin, bifacial, pubescent beneath, especially when young. 



Epidermis; Ventnd cells containing mucilage, radial walls not 

 undulate; cuticle striate. Dorsal cells much smaller, 1 radial walls 

 slightly undulate, Stomata on the dorsal surface only, lying in all 

 directions, level with the surface, each bordered by 4 or 5 undifferen- 

 tiated epidermis cells. Hairs, confined to the dorsal surface in mature 

 leaves, of two kinds: (1) Abundant along the veins, long, pointed, 

 with thick, warty cuticle, unicellular, and (2) much fewer, small, thin- 

 walled, clavate, unicellular, probably glandular. 



Palisade in one layer. Pneumatic tissue rather open. Sclerotic 

 idioblasts extending from the ventral almost to the dorsal epi- 

 dermis. 



'The outer walls of the colls of the dors;d epidermis are described as " papil- 

 lose] y convex " by Sertorius (Bull, de l'Herb. Boiss., vol. 1, p. 633), 



