Text-book of botany, morphological and physiological . roductivepower, the Soredia. This term is applied to single gonidial cells or groups of gonidia which,surrounded by a weft of hyphae, are pushed out of the thallus, and are able, without anyfurther process, to grow into a new Lichen-thallus. The soredia are produced from thethallus in the non-gelatinous Lichens as a fine powder, forming sometimes dense pulvinatemasses (as in Usnea, Ramalina, Evernia, Physcia, Parmelia, Pertusaria, &c.). In theheteromerous thallus the soredia appear in the gonidial layer; single gonidia, or some-times sever
Text-book of botany, morphological and physiological . roductivepower, the Soredia. This term is applied to single gonidial cells or groups of gonidia which,surrounded by a weft of hyphae, are pushed out of the thallus, and are able, without anyfurther process, to grow into a new Lichen-thallus. The soredia are produced from thethallus in the non-gelatinous Lichens as a fine powder, forming sometimes dense pulvinatemasses (as in Usnea, Ramalina, Evernia, Physcia, Parmelia, Pertusaria, &c.). In theheteromerous thallus the soredia appear in the gonidial layer; single gonidia, or some-times several together becoming woven over by branches of hyphae which cling closely tothem and form an envelope of fibres. The gonidia divide repeatedly, and each daughter-cell is again woven over. This process is often repeated, the soredia accumulate ingreat numbers in the gonidial zone, and finally rupture the cortex. After escaping in ;: THALLOPHYTES. this manner, the soredia can still further multiply outside the thallus; but under favour- s oO^°
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
