40 

 3. Another objection is that tropical plants show the most color. 

 Overton published an article upon coloration in plants. 

 His theory is that the amount of sugar in a plant depends on the 

 amount of red color. Spring and fall, times of the conduction 

 of sugar. A third view is that color, especially green color, 

 has no ecological meaning. 



Read — Coulter — Chapter V. --Roots, also Disc\i.ssion of 

 Xerophytes — p. 193. Warm.ing — p. 177 — on. 



Laboratory Outline . 

 Absorption . 

 Root-hairs, typical structure in any plant. 

 RhijEoids in mosses and liverworts. 

 Leucohryium and Sphagnum. 

 Hair on Chickweed or Stellaria. 

 Parasitic absorption in Cuscuta. 

 Mycorhiza oiff Alder. 

 Legume tiibercle. 

 Monotropa imiflora. 

 Aselepias roots. 

 Lichen. 



