. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. OVULES OF CYCADS 325 siderable size, but contain only a single large megaspore {p.) within the several-laj'ered parenchymatous wall or niicdlus (».). The delicate texture of the latter can be related to the presence of a thick fleshy protective covering (0. and i.). This integument. Fig. 185.—A, Megasporophyll of Cycas revoliUa with four ovules (about half natural size). B, Mature megasporophyll of Encephalartos hil- denbrandtii, bearing two seeds (about half natural size). D, Diagram of longitudinal section
. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. OVULES OF CYCADS 325 siderable size, but contain only a single large megaspore {p.) within the several-laj'ered parenchymatous wall or niicdlus (».). The delicate texture of the latter can be related to the presence of a thick fleshy protective covering (0. and i.). This integument. Fig. 185.—A, Megasporophyll of Cycas revoliUa with four ovules (about half natural size). B, Mature megasporophyll of Encephalartos hil- denbrandtii, bearing two seeds (about half natural size). D, Diagram of longitudinal section of ovule of Boivenia speciabilis, and C, front end of same enlarged. ar., archegonia ; «., inner fleshy layer of integu- ment ; , vascular bundle of inner series ; mi., micropyle ; «., nucellus ; 0., outer fleshy layer of integument ; , bundle of outer series; ;^., female prothallus within megaspore; , pollen chamber; , pollen tube ; s., stony laj'er of integument. (A and B original ; C and D after Kershaw.) complete^ envelops the nucellus, and is indeed fused with it except at its extreme apex. In this region the integument is pierced b}? a narrow canal, the micropyle (»n'.), leading down to the tip of the nucellus, in which a conical cavity, the pollen chamber {), is formed b}' the breaking down of the tissue. The ovule is. 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 Fritsch, Felix Eugene, 1879-; Salisbury, E. J. (Edward James), Sir, b. 1886. London, G. Bell and sons ltd.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpl, booksubjectplants
