. Botany for high schools and colleges. Botany. 370 BOTAJsrr. and is generally provided with root-hairs on its under sur- face, by means of which it secures nourishment for its inde- pendent growth (Pig. 252). In the Rhizocarpece the pro- thallium is so reduced as to be only a small outgrowth of the germinating spore. 486.—Both kinds of sexual organs usually occur upon the same prothallium. The antheridia consist of a few or many sperm-cells, which may or may not bo surrounded by a wall. T^G. 253. FiQ. 253. Fig. 353.—A prothallimn of a fern, seen from the under side. A, the root-liairs grow- i
. Botany for high schools and colleges. Botany. 370 BOTAJsrr. and is generally provided with root-hairs on its under sur- face, by means of which it secures nourishment for its inde- pendent growth (Pig. 252). In the Rhizocarpece the pro- thallium is so reduced as to be only a small outgrowth of the germinating spore. 486.—Both kinds of sexual organs usually occur upon the same prothallium. The antheridia consist of a few or many sperm-cells, which may or may not bo surrounded by a wall. T^G. 253. FiQ. 253. Fig. 353.—A prothallimn of a fern, seen from the under side. A, the root-liairs grow- ing from the basal end of the prothallium ; an, the antheridia scattered among the root-hairs ; ar, archegonia near the apex. X 10.—After Prantl. Fig. 253.—Mature antheridium of .4(iiorefem CapUlus-YeMru. p, cells of prothal- lium : a, wall of antheridium—the sperm-cells are seen escaping, in each a sperma- tozoid is coiled up ; 5, thespermatozoids ; 6, the protoplasm of the sperm-cells still attached to the spermatozoids. X 650.—After Sachs. of other cells. In the Ferns {Filices) they are few-celled bodies, which project from the basal portion of the under surface of the prothallium ; one of the interior cells becomes divided into sperm-cells, in each of which is a spirally coiled spermatozoid (Fig. 353). In the other orders the antheridia are not confined to the under surface of the prothallium, and in some of the Rhizocarpem nearly the whole of the contents of a microspore is developed into one antheridium filled with sperm-cells,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bessey, Charles E. (Charles Edwin), 1845-1915. New York : H. Holt
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1885
