110 STUDY OF COMMON PLANTS. 



a moist atmosphere for a week or two. By this means the 

 relation of rhizoids and protonema is made clear. It is 

 seen that they are the same thing, the filamentous growth 

 taking the appearance and structure of protonema or 

 rhizoids according to the conditions under which it grows. 

 It is also seen that the protonema may originate from 

 other parts of the plant, as well as from the spore. 



On the protonema, whether it has its origin in the spore, 

 or from some other part of the plant, buds arise, from which 

 new plants are formed. 



Archegoiiia and Antlieridia. 



Among the specimens, if these have been gathered at dif- 

 ferent times of year, some will be likely to show "flowering 

 heads," most frequently terminating the stem, and sur- 

 rounded by a more or less conspicuous rosette of leaves, 

 the perichaetium. The antheridia and archegonia may 

 occur together in the same " flower," or in separate flow- 

 ers, on the same or on different individuals. 



The whole structure is best studied by means of longi- 

 tudinal sections, which are easily made with a razor, after 

 a little practice, without any previous preparation of the 

 specimen. Examining such sections under the microscope, 

 if we chance to have selected a male specimen we shall 

 find antheridia in great numbers growing at the apex of 

 the axis, and with them slender, filamentous bodies, para- 

 physes, while outside of both is the circle of perichsetial 

 leaves. The antheridia are sacs, usually oblong in shape, 

 with a wall consisting of a single layer of cells, the interior 

 being composed of the mother cells of the antherozoids. 

 The latter are ciliated, protoplasmic bodies, closely resem- 

 bling those of the ferns. In the examination of a female 

 specimen the paraphyses are seen as before, but archegonia 



