. The microscope and its revelations. and of darkness and moisture 011 the other, anyattempt to alter it is found to be vain; for if the surfaces of theyoung fronds be then inverted, a twisting growth soon restores themto their original aspect. When Ma/rchantia, vegetates in damp shady situations whichare favourable to the nutritive processes, it does not readily producethe true fructification, which is to be looked for rather in plantsgrowing in more exposed places. Each of the stalked peltate(shield-like) discs contains a number of flask-shaped cavities openingupon its upper surface, which a
. The microscope and its revelations. and of darkness and moisture 011 the other, anyattempt to alter it is found to be vain; for if the surfaces of theyoung fronds be then inverted, a twisting growth soon restores themto their original aspect. When Ma/rchantia, vegetates in damp shady situations whichare favourable to the nutritive processes, it does not readily producethe true fructification, which is to be looked for rather in plantsgrowing in more exposed places. Each of the stalked peltate(shield-like) discs contains a number of flask-shaped cavities openingupon its upper surface, which are brought into view by a verticalsection; and in each of these cavities is lodged an antherid whichis composed of a mass of sperm-cells, within which are developedantherozoids like those of Chora; the whole being surmounted bv along neck that projects through the mouth of the flask-shaped wheel-like receptacles (fig. 503). on the other hand, bear on theirunder surface, at an early stage, concealed between, membranes that. PIG. 505.—Gemmiparous conceptaclesotMcurchantiapoh/morpha: A, con-ceptacle fully expanded, rising fromthe surface of the frond, a. a, andcontaining goiiidial gemma- alreadydetached. B, first appearance ofconceptacle on the surface of thefrond, showing the formation of itsfringe by the splitting of the epiderm. 668 MICROSCOPIC STRUCTURE OF HIGHER CRYPTOGAMS connect the origins of the lobes with one another, a set of like flasks with elongated necks (fig. 507); each of these hasin its interior an oiisphere or germ-cell, to which a canal leadsdown from the extremity of the neck, and which isfertilised by the penetration of the antherozoidsthrough this canal until they reach it. Instead,however, of at once evolving itself into a new plantresembling its parent, the fertilised oosphere orembryo-cell develops itself into a mass of cells en-closed within a capsule, which is termed a sporange ;and thus the mature receptacle, in place of
Size: 1595px × 1567px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
