73» 



LECTURE XLI. 



B and C. It will be noticed how the neck h of the archegonium, which has now 

 turned red, and is decaying, is still situated above. This still growing venter, 

 investing the embryo as a loose sac, is the Calyptra. 



Enclosed within the calyptra the embryo of the ]\ross now grows up into a long 

 approximately spindle-shaped bodyy^ the lower end of which bores into the tissue 

 of the Moss-stem, but without coming into true organic connection with it. When 

 this elongated embryo has attained a certain length, the calyptra tears away near its 

 base : the lower part remains attached to the stem as the so-called vaginula, while 



Fig. ^K^—Fiiuarin hygro 

 ception of the sporogoniuin //' in the ventral 

 portion bb o{ the archegonium (optical long, sec, 

 XSoo)- B, C, further stages of development of the 

 sporogoniumy'and of the calyptra f ; A neck ol 

 archegonium X (about 40). 



Fig, 420. — Fu}taria hygro>netrica. A 

 leafy stem g with calyptra c. B a. plant .j- 

 with sporogonium nearly ripe : j seta ; y 

 capsule ; c calyptra. C longitudinal median 

 section of the capsule (urn): (^operculum ; a 

 annulus; p peristome cc' columella; h air- 

 sp.ace. 5 primary mother-cells of the spores. 

 The tissue of the columella becomes loose 

 and filamentous below. 



the whole of the upper part of the calyptra is carried up by the elongating embrj'o, 

 which it invests closely, and by which it is nourished. The upper portion of the still 

 stalk-like embryo, within the calyptra, now swells out and becomes thicker: this 

 forms the spore-capsule of the Moss-fruit, the calyptra still remaining on it. 



It would require too much space to describe in detail the development of the 

 Moss-fruit: all that is necessary may be explained by means of Fig. 420. Here is 

 shown {c in A ) the calyptra still enveloping the whole of the embryo ; at B the latter 

 has already become developed into the Moss-fruit or Sporogonium, consisting of 

 a long thin stalk s (Seta), and the spore-capsule / (Theca) on which the calyptra 



