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of long palisade cells over a spongy parenchyma which has 

 its lowest (green) layer of cells slightly palisade-like, and 

 below this is still another palisade-like layer of cells which 

 is colourless and must be designated an aqueous tissue. 



Fig. 66. Ceratocarpus arenariiis. A, A young plant with green leaves and 



a few fruits in the axils. May. (natural size). B, An older, plant, (reduced 



one-half). C, A branch of B, (X 2). The parenchyma has disappeared 



and the midribs remain as spines. August. 



Ceratocarpus arenarius L. 

 This very common plant occurs both on sandy and 

 clayey soil; Fig. 66 shows its appearance. In spring the 



