lo 



VORKSMIUK NATUkALTSTS* UNION. 



the upper, the calyptra, which is expanded by tlie growing 

 capsule, and it is only when the seta has attained its full length 

 that the capsule begins to enlarge and form spores ; the seta is 

 of firm consistence, and smooth or rough with small nodules, 

 and its length varies greatly. 



The calyptra protects the young capsule and is constant in 

 form, commonly cucullate or dimidiate when oblique, and split 

 up on one side^ or mitriform when erect, regular and slit into 

 several lobes; in a few it is shaped like an extinguisher, and 

 occasionally the mouth is fringed ; the surface is smooth or 

 hairy, papillose or spinulose. 



i 



+ 



The fulbgrown capsule, tbeca, or sporangium may be 

 regular or symmetric, or it may be irregular or unsymmetricj 

 and its form is very variable, pear-shaped, globose, oblong, 

 cylindric, or angular, and in direction erect, drooping, or pen- 

 dulous ; the surface has an epidermal layer of flat empty cells, 

 generally furnished with stomata, by which communication is 

 maintained between the atmosphere and the interior of the 

 capsule ; these stomata have two guard-cells, and they are also 

 found on some leaves. A flask-like enlargement is sometimes 

 seen below the capsule, called the hypophysis, notably in the 

 Splachnace^, in which it is much larger than the capsule itself. 



The capsule is a most important organ, and extremely 

 beautiful in structure, and perhaps we shall get the best idea of 

 its formation by a section. We see that it consists of an external 

 wall of several layers of cells, next to this an air-cavity, often 

 bridged across by small cellular ropes or threads reaching to the 



1 



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But. Trans. Y.N.U., 181)1 ([uib. 18UG). 



