The encyclopdia britannica; a dictionary of arts, sciences, literature and general information . ticae (Liverworts). The range of form and structure of both generations in theliverworts is so great that no one form can be taken as a satis-factory type. It will, however, be of use to preface the moregeneral description by a brief account of a particular example,and we may take for this purpose a very common and easilyrecognized thalloid liverwort belonging to the Junger-manniales. Pellia epiphylla (fig. 2) can be found at any season growingin large patches on the damp soil of woods, banks, &c.
The encyclopdia britannica; a dictionary of arts, sciences, literature and general information . ticae (Liverworts). The range of form and structure of both generations in theliverworts is so great that no one form can be taken as a satis-factory type. It will, however, be of use to preface the moregeneral description by a brief account of a particular example,and we may take for this purpose a very common and easilyrecognized thalloid liverwort belonging to the Junger-manniales. Pellia epiphylla (fig. 2) can be found at any season growingin large patches on the damp soil of woods, banks, &c. The broadflat thallus is green and may be a couple of inches long. It issparingly branched, the branching being apparently dichoto-mous; the growing point is situated in a depression at theanterior end of each branch. The wing-like lateral portionsof the thallus gradually thin out from the midrib; from theprojecting lower surface of this numerous rhizoids are elongated superficial cells, and serve to fix the thallusto the soil and obtain water and salts from it. No leaf-like. appendages are borne on the thallus, but short glandular hairsoccur behind the apex. The plant is composed throughoutof very similar living cells, the more superficial ones contain-ing numerous chlorophyll grains, while starch is stored in theinternal cells of the midrib. The cells contain a number of oil-bodies the function of which is imperfectly understood. Thegrowth of the thallus proceeds by the regular segmentation of asingle apical cell. The sexualorgans are borne on theupper surface, and bothantheridia and archegoniaoccur on the same branch(fig. 3, A). The antheridia(on) are scattered over themiddle region of the thallus,and each is surrounded bya tubular upgrowth fromthe surface. The archegonia(ar) are developed in agroup behind the apex, andthe latter continues to growfor a time after their forma-tion, so that they come tobe seated in a depressionof the upper surface. Theyare further
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
