528 



HUTGHINSON'S POPULAR BOTANY 



The archegone has an enlarged lower portion containing the oosphere, and 

 an upper neck with its canal, through which the antherozoids gain access to 

 the oosphere. After fertilization the oosphere develops into the sporogone, 

 usually elevated on its stalk, which carries it up through the calypter ; this 

 is the entire non-sexual generation. In Riccia the sporogone is immersed 

 in the thallus. Among the spores are long attenuated cellular bodies, the 

 elaters, whose walls are furnished with spirally twisted threads, which are 

 hygrometric and cause the twisting of the elaters as they absorb or part 

 with moisture. Their movements under this influence assist in the dispersal 

 of the spores. The spores may be invested in one, two, or three coats, but 



usually two. 



The popular name Liver- 

 wort, applied to the larger 

 and more conspicuous mem- 

 bers of this class, is, as its 

 Saxon termination shows, 

 an old folk-name. The ap- 

 pearance of the epidermal 

 cells and the shape of the 

 fronds were supposed to be 

 in little a picture of the 

 human liver, and to indicate 

 under the Doctrine of Sig- 

 natures that it was to be 

 used as a medicine in liver 

 troubles. As late as the 

 middle of the seventeenth 

 century we find Nicholas 

 Culpeper, who was great on 

 Signatures, describing the 



vhich is shown more highly magnified in the second figure. The round T ilVPrwnrt flQ " n ciri mild Y- 

 and oval forms between the hyphce represent the algal elements. Ljl ^ erWOr a Singular 



good herb for all the diseases 



of the liver, both to cool and to cleanse it, and helpeth the inflammations in 

 any part, and the yellow jaundice likewise," and ." an excellent remedy for 

 such whose livers are corrupted by surfeits, which cause their bodies to 

 break out, for it fortifieth the liver exceedingly, and makes it impregnable." 

 It had to be " bruised and boiled in small beer and drank," but with the 

 happy-go-lucky methods of prescribing in his day, he omits to say whether 

 a dose consisted of a tablespoonful or a quart. The open-air exercise 

 involved in a search for the numerous species would probably do far 

 more to keep the liver normal than a barrel of Culpeper's small beer in 

 which Marchantia polymorpha had been boiled. More than two hundred 

 and sixty species of the Hepaticse are known to inhabit the British 

 Islands, and though they are all comparatively small plants, they are in 



FIG. 672. SECTIONS THROUGH LICHEN. 



In the left-hand figure the loose hyj. 



rkc.l 



the gonidial layer, 



