. The vegetable kingdom : or, The structure, classification, and uses of plants, illustrated upon the natural system. al plants, often spreading over the surface of the earth, or rocks, or trees, indry places, in the form of a lobed and foliaceous, or hard and crustaceous, or leproussubstance, called a thallus. This thallus is formed of a cortical and medullary layer,of which the former is simply cellular, the latter both cellular and filamentous ; in the crustaceous species the cortical andmedullary layer differ chiefly in tex-ture, and in the former being co-loured, the latter colourless ; b
. The vegetable kingdom : or, The structure, classification, and uses of plants, illustrated upon the natural system. al plants, often spreading over the surface of the earth, or rocks, or trees, indry places, in the form of a lobed and foliaceous, or hard and crustaceous, or leproussubstance, called a thallus. This thallus is formed of a cortical and medullary layer,of which the former is simply cellular, the latter both cellular and filamentous ; in the crustaceous species the cortical andmedullary layer differ chiefly in tex-ture, and in the former being co-loured, the latter colourless ; but in thefruticulose or foliaceous species, themedulla is distinctly floccose, inthe latter occupj-ing the lower half ofthe thallus, in the former enclosed allround by the cortical layer. Repro-ductive matter of two kinds ; 1, spoiesnaked, or lying in membranous amy-laceous tubes (thecse) immersed innuclei of the medullary substance,which burst through the corticallayer, and colour and harden by ex-posure to the air in the form of littlediscs called shields ; 2, the separatedThese, called gonidia, or gongyh, are. %,;>^^^^7 f^i^}^ IJ11^.- \o,])) it^^^vV/ ^ ^^ Fig. XXX. cellules of the medullary layer of the thallus. Fig. Shields of Variolaria amara ; 2, a portion of the thallus of the same plant; o. apiece of the thallus of Sticta pulmonacea, with lacunae and soredia ; 4. thallus of the same, bearingshields : 5- shield of Opegrapha scripta ; 6. thallus of the same ; 7. shields, young and old, of Lecanoraperella; 8. shields of Bzeomyces rufus ; 9. part of thallus of Peltidea canina; 10. section of a shieldof Sticta pulmonacea ; 11. Podetia of Cenomyce coccinea; 12. section of a shield of Baeomyces rufus ;13. shields of Endocarpon miniatum ; 14. thallus of the same. Chiefiy from Grevilles Flora Edmensis. Fig. XXX.—Section of a shield of Parmelia parietina. Link. 46 LICHENALES. [Thallogens.
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Keywords: ., bo, bookcentury1800, bookdecade1840, bookidvegetablekingdom00lind