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A TEXTBOOK OF BOTANY 



[Cn. XI 



The typical life cycle in true Mosses is illustrated in Figure 

 346. On the upright leafy stems, which are the garnet o- 

 phytgs^fl.re borne the sporogonia, which are the sporophytes. 

 The latter consist of spore capsules at the summit 



FIG. 346. The life cycle of a Moss, mostly Polytrichum. 



Left, the plant ; X y. Next, above, the capsule, in vertical median 

 section, X 6, with spore and germinating spore, X 300, and a spore germi- 

 nated to a protonema bearing a bud from which develops the familiar leafy 

 plant, X 75. Below, archegonial shoot, X 2 ; with archegonium in section, 

 X 16, antheridial shoot, X 2, with antheridium, X 16, and single sperm cell, 

 X 600. Last, developing sporogonium, showing origin of calyptra from 

 enlarged archegonium. (After Dodel-Port, and other sources.) 



slender SET^E ; and they are usually capped by the CALYPTRA,. 

 a loose conical cover which is a relic of the archegonium. _Thfi 

 _sporej;apsule jnjjietrue Mosses is a highly specialized struc- 

 ture. At its base is a swelling, the APOPHYSIS ; at its tip is 

 aTcap, thTTopERcuLUM, which falls off at maturity, releasecT 



