138 



STRUCTURAL BOTANY 



functions. The whole capsule is covered- by a well- 

 marked epiderm's, which, on the apophysis, contains 

 stomata. In the upper part of the capsule the wall is 

 several cells in thickness ; the 

 hypodermal layers are colourless, 

 while those towards the interior 

 contain chlorophyll. Connected 

 with these inner cells of the wall 

 are filamentous strands, also con- 

 taining chlorophyll, which extend 

 across the intercellular space, 

 and form a junction with the 

 internal tissues. The central 

 mass is narrow below and ex- 

 panded above, assuming a barrel- 

 like shape. It is from this part 

 that the spores are produced. 

 The archesporium forms at first 

 a single cellular zone,, which 

 has a hollow cylindrical form, 

 or, more accurately, is shaped 

 just like a barrel with the ends 

 knocked out (see Fig, 63, a). 

 The archesporial layer is separ- 

 ated from the intercellular space 

 by a zone of sterile tissue called 

 the outer spore-sac. Within the 

 archesporinm is the large central 

 mass of sterile colourless tissue 

 (the columella), which is con- 



FIG. 63. Capsule of Funaria 

 inlongitudinalsection. ap, 

 the apophysis ; a, a, the 

 archesporium, forming a 

 single layer of cells (lightly 

 shaded) ; it surrounds the 

 columella, c. The green 

 assimilating tissue is dark- 

 ly shaded. The operculum 

 closes the top of the cap- 

 sule, above the columella ; 

 its individual cells are not 



shown. The dark spots 



in the epidermis of the nected below by a thinner strand 



stomata. Magnified 14. " * 



(After Haberlaudt.) The layer between archesporium 



