332 FUNABJA. 



471. Male Flowers of Miiium. Instead of, or in addition to, 

 the male shoots of Funaria, examine those of Mnium hornum, a 

 very common Moss found in shady moist places in woods, in dark- 

 green patches, often about 5 cm. high, with star-like male flowers 

 which are very conspicuous in spring and early summer. In Mnium, 

 the paraphyses have no swollen cells at the top, and the dehiscence 

 cap of the antheridium consists of a group of cells. 



472. Archegoiiia. Examine some of the plants on 

 which no sporogonia can be seen, and cut off the bud-like 

 tips of the shoots, which are likely to show archegonia ; 

 tease up some of these in water, make longitudinal sections 

 of others, and look for the archegonia, which are seated 

 on the apex of the stem and are enclosed by the uppermost 

 leaves, and accompanied by paraphyses. 



In an archegonium note the relatively long and thick 

 stalk, the slightly enlarged venter consisting of two 

 layers of cells, and the long neck ; the structure is essen- 

 tially the same as in Pellia. If the organ is not too old, 

 the central series of cells may be seen the oosphere and 

 ventral canal-cell in the venter, the neck canal-cells 

 in the long neck ; if it is ripe and has opened, the canal- 

 cells will have disappeared, leaving only the oosphere (or 

 the embryo sporophyte developed from the fertilised 

 oosphere) in the venter. 



473. Stages in Development of Sporogonium. 



Examine with the low power a series of female shoots 

 showing different stages in the growth of the sporogonium. 

 The withered archegonium neck can be seen at the top of 

 the calyptra (enlarged venter of fertilised archegonium), 

 which is swollen at the base. Treat with potash, or cut 

 longitudinal sections, to see the young sporogonium as 

 an elongated rod with pointed upper and lower ends, the 

 upper part closely invested by the narrow upper portion of 

 the calyptra, while towards the base it is separated from 

 the calyptra by a liquid-containing space (seen externally 

 as a swelling), and its pointed lower end is plunged in the 

 tissue of the stem. 



Lay in water on a slide a plant with a young sporo- 

 gonium, and with the fingers or a needle carefully remove 



