9 6 



Elementary Plant Physiology. 



Fig. 68. Cuscuta attached to stem and 

 leaves of an aster. After Johnson. 



converted into starch in leaves in which the stomata are 

 closed ? 



99. Nutritive relations of a parasite. Secure some 



living specimens of Cuscuta, 

 or dodder, to be found as 

 yellow cord-like stems, at- 

 tached to Impatiens and 

 other plants on the margins 

 of swamps and in meadows 

 in late summer. Examine 

 fresh material, and place 

 remainder in formalin or 

 alcohol. Note manner in 

 which the dodder is attached 

 to the host plant. Cut thin 

 sections through the organs of attachment and the stem 

 which they penetrate, and make out the anatomical relations 

 of the two plants. It will be profitable to secure seeds of the 

 parasite and grow 



them in a pot jj A. 



containing young 

 plants of tomato, 

 or other herba- 

 ceous species, and 

 note the manner 

 in which the para- 

 site attacks and at- 

 taches itself to the 

 host plant. 



Cut a section of 

 a leaf of any seed 

 plant which has 

 been attacked by F *- ^-^ roots of beech <**""> cov< f d with a 



symbiotic fungus ; B, terminal portion of root en- 

 a parasitic fungUS, larged. After Frank. 



