Text-book of botany, morphological and physiological . FIG. 265.—Under sideof a lacinia of a leaf ofAspidiwn Filix-nias,with eight indusia i (X2).. Fig. ?ifA.—Aspidium. Filix-ntas. A transverse section of a leaf with a sorus consisting of the sporangia s and theindusium ii; right and left in the mesophyll of the leaf are two small fibro-vascular bundles, the sheath of which showsthe dark brown thickenings on the walls that face inwards. B a young sporangium, its annulus standing vertically tothe plane of the paper, r its apical cell; in the interior four cells are seen resulting from the divis
Text-book of botany, morphological and physiological . FIG. 265.—Under sideof a lacinia of a leaf ofAspidiwn Filix-nias,with eight indusia i (X2).. Fig. ?ifA.—Aspidium. Filix-ntas. A transverse section of a leaf with a sorus consisting of the sporangia s and theindusium ii; right and left in the mesophyll of the leaf are two small fibro-vascular bundles, the sheath of which showsthe dark brown thickenings on the walls that face inwards. B a young sporangium, its annulus standing vertically tothe plane of the paper, r its apical cell; in the interior four cells are seen resulting from the division of the central cell;C lateral view of a nearly ripe sporangium, rr its annulus, d the stalked gland peculiar to this species ; within the sporan-gium are seen the young spores already formed. seated on the end of a vein, which then frequently puts out two branches in the angleof which is placed the sorus, or it may be formed on the back and below the ends ^ Athough these points of structure are employed in systematic botany as characters of families,their morphology is at present but little known. A history of the development of the
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
