. Botany for high schools and colleges. Botany. 384 BOTANY. Order Lycopodiaceee.âThe prottallinm is known only in one case, viz., Lycopodmm, annotinum-. It was discovered underground by Fankhauser in 1873, who described it* as a yellowish white, irreg- ularly lobed body, sparingly furnished on its under surface with small root-hairs (Fig. 374, A). In its upper surface the prothallium bears antheridia, which are deeply sunken in its tis- sue {an. Fig. 274, A); the spermatozoids, which are numerous, are stout and slightly twisted. The archegonia were only seen after the young plants had grown co
. Botany for high schools and colleges. Botany. 384 BOTANY. Order Lycopodiaceee.âThe prottallinm is known only in one case, viz., Lycopodmm, annotinum-. It was discovered underground by Fankhauser in 1873, who described it* as a yellowish white, irreg- ularly lobed body, sparingly furnished on its under surface with small root-hairs (Fig. 374, A). In its upper surface the prothallium bears antheridia, which are deeply sunken in its tis- sue {an. Fig. 274, A); the spermatozoids, which are numerous, are stout and slightly twisted. The archegonia were only seen after the young plants had grown con- siderably (Fig. 274, B); they are likewise devel- oped upon the upper surface of the prothal- lium, and appear to bear a considerable resem- blance to those of the Op7uoj!ossacem. The young plant which results from the growth of the fertilized germ- cell is quite simple, but it soon takes on the form of the mature plant. The leaves are crowded in Lycopodium, but are less so in tlie other gen- era. In many species the sporangia are borne in the axils of the or-. Fig. 276 âGiTmination of the spores of Selaginaia. 1, longitudinal i^ection of a macrospore of S. Murten- aii; above the line d is the prothallium, below it the " endosperm ;" «,«', two embryos, the laiger one with its suepensor projecting into the nect of the archego- â ; left â ' nium ; at the 1 chegonium ; several root of the larger embryo is a young ral root-hairs are also shown. S young archegonium of the same species, not yet open 3, an archegonium of the same species, with the germ- cell fertilized and divide d into two. A, a microspore of S. caulescens, rendered transparent, showing the di- vision of the contents into the primordial cells; the small lower cell is the rudimentary prothallium. D, later stage of the same, showing the large antheridium filled with sperm-cells ; t), the rudimentary prothal- lium. All magnified.âAfter Pfeffer. 2, a dinary leaves, but in others the leaves which b
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1885
