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A TEXTBOOK OF THEORETICAL BOTANY 



The structure of the prothalkis varies greatly in the different species of 

 Lycopodiiim. In L. clavatum it is a much convoluted structure i to 2 cm. long, 

 with a pointed basal part. The surface is covered with an epidermis, inside 



Sporophyll 



Sporangiophore 



Sporangium 



Fig. 580. — Lycopodhim claratinn. Longitudinal section of the 

 strobilus showing origin of the sporangia from the upper 

 surface of the sporophylls. 



which is a cortex of several layers, followed by a palisade tissue composed 

 of a single layer of elongated cells. These outer layers contain the endo- 

 phytic Fungus. This is followed by a central tissue of hexagonal cells whose 

 function is to store up food material. All these tissues form a wedge-shaped 

 structure which has a more or less flat top. The core of the wedge and the 



