MICROSCOPIC STRUCTURE OF WEED SEEDS 579 



Chicory {Cichorivm intybus L.). 



The microscopic structure of the pericarp and seed of chicory 

 has been given by Harz and Lavialle. The pericarp consists of 

 epidermal cells whose outer walls are irregular and cuticularized. 

 This is followed by a variable number of rows, usually 10-15, of 

 sclerotic parenchyma, some of the cells of which as observed by 



er 



en 



Fig. 441. Microscopic structure of the seed of Chicory (Cidhorium imtj/Bus). 



ep=epidermis. sol=sclerotic parenchyma. per=pericarp. t=testa. al=aleu- 



rone layer, en = endosperm. 



(Drawing by Charlotte M. King and D. H. Fammel.) 



Kraus, contain crystals of calcium oxalate. Beneath are 6-8 rows 

 of thin-walled, elongated parenchyma. The testa consists of a layer 

 of large epidermal cells, followed by smaller thin-walled parenchy- 

 ma, thte inner portion much compressed. The aleurone layer is 

 of elongated cells containing aleurone grains. 



Dandelion {Taraxacwm, officinale Weber). 



Harz has given an account of the structure of the pericarp and 

 seed. The epidermal cells are irregular, many of the cells pro- 

 longed into one-celled trichomes, the ribs forming tubercular 

 processes. The underlying portion containing the thinner-walled 

 parenchyma and the sclerotic parenchyma cells of the ribs. This 

 is followed by several rows of compressed, elongated, thin-walled 

 parenchyma cells. The testa consists of the epidermal layer of 

 elongated, spirally thickened walls, followed by a compressed layer 

 of parenchyma cells. The endosperm of one or two rows of 

 aleurone cells. 



