BBTOPHTTA. 191 



different parts of the same plant (monoecious) or even 

 upon different plants (dioecious). 



398. The act of fertilization requires water; but as th?> 

 antherozoids are so minute, a dew-drop may be sufficient. 

 The antherozoids swim to the open neck of the archegone, 

 down which they pass to the germ-cell. The germ-cell 

 now begins to divide rapidly, growing upward and eventu- 

 ally forming the spore-fruit. In most mosses the spore- 

 fruit is narrow and elongated below, forming a stalk which 

 supports its upper spore-bearing part (the capsule or spore- 

 case). 



399. The spore-case, when ripe, usually opens by a lid 

 which falls off, leaving a round opening, generally fringed 

 with many teeth (Fig. 106, G and H). In most species, as the 

 spore-fruit elongates it carries up the remains of the dis- 

 tended archegone as a little cap (calyptra) (Fig. 106, E, c). 



400. The spores, which are round or angular cells con- 

 taining protoplasm, chlorophyll-granules, oil-drops, etc., 

 germinate quickly upon moist soil. Each spore protrudes 

 a tubular filament, which develops into a conferva-like 

 branching growth of green cells, called the protonema (Fig. 

 107). Upon this there finally are produced buds from 

 which spring up the leafy stems, thus completing the round 

 of life. 



401. There are four orders of Mosses, as follows: (1) the 

 Peat-mosses (Order Sphagnacese), composed of large, soft, 

 and usually pale -colored plants, with clustered lateral 

 branches; they inhabit bogs and swampy places, where 

 they form dense moist cushions, often of great extent. On 

 account of peculiarities in the structure of their leaves they 

 are enabled to absorb and hold large quantities of water, 

 and for this reason they are extensively used for " packing" 



