of Imperfect Plants. 257 



of small and herbaceous plants resembling the mosses, but 

 chiefly constituting fronds, and producing their fruit in a cap- 

 sule that splits into longitudinal valves. Their name is de- 

 rived from a Greek word, »j7r«g, yjiraroj, signifying the liver; 

 because, perhaps, some of them were formerly employed as a 

 remedy in diseases of the liver, or exhibit a slight resem- 

 blance to the lobes of that organ. Their favourite habits are 

 wet and shady spots by the sides of springs and ditches, and 

 their vegetation is always the most rapid in cold and damp 

 weather. 



Many of them have no root, or at least no conspicuous 

 root, &s Jungermannia asplenioides; but where a root is present 

 it is fibrous. In the greater number of them the herbage is 

 frondose, though not upright as in the ferns, but creeping 

 along upon the surface of the soil, and striking root as it ex- 

 tends. It is rather lobed than leaf-like, with the lobes over- 

 lapping, and exhibiting under the microscope a fine network 

 of vesicles frequently transparent. 



The fructification of the liverworts is analogous to that of the 

 mosses. According to Hedwig, the barren flowers are either 

 small and globular protuberances issuing from the summit 

 of the plant, or small and minute granules imbedded in the 

 body of* the frond, or in target-shaped substances elevated on 

 a conspicuous pedicle as in Marchantia. The fertile flowers, 

 for the most part, but particularly in the genus Jimgermannia, 

 are furnished with a double envelope ; the outer correspond- 

 ing in some degree to the calyx, and the inner, which imme- 

 diately invests the ovary, to the corolla of perfect plants. If 

 the flower is left to ripen, the envelopes will, in the process of 

 fructification, burst open at the top, and discover a small pro- 

 truding globule, of a black or brownish colour, and of about 

 the size of a millet-seed, which is by and by disengaged from 

 the envelopes entirely, and elevated on a fine and thread- 

 shaped pedicle from a line to an inch in length. This ele- 

 vated globule is the ovary, which when ripe separates into 

 four longitudinal valves, from the extremities of which a num- 

 ber of small spiral and elastic threads issue, to which the seeds 

 or sjxmdcs are attached. 



The Algcc, or Flags. — The term Algcc, which is of Latin 

 origin, and which we translate Flags, seems, primarily, to have 

 denoted any sort of plant or herb growing in sea-water. 



Cras foliis nemus 



.Multis, et alga littus inuhli. 

 Demissii tempestas ah Euro, 

 Sternet. — llor. lib. iii. Ode xvii. 



Yet botanists have extended its application to many plants 



Third Series. Vol. +. No. 22. April 1 83+. 2 L 



