. Plants and their uses; an introduction to botany . Fig. 370.—Scouring-rush. A, male gametophyte or piothallus (152) show-ing antheridia (a, a). B-E, spermatozoids of various ages, muchmore highly magnified. (Hofmeister, Schacht.) Fig. 371.—Scouring-rush. Female gametophyte or prothallus (^1^-) showingarchegonia (a, a, a) and pseudo-roots (h). (Hofmeister.) in a cone-like aggregation of whorled sac-leaves. Each ofthese has a stalk ending in a shield-shaped expansion, six-sided from pressure. Behind each angle of the shield is alarge sporangium dehiscing by a longitudinal slit (3, 4)-The spore
. Plants and their uses; an introduction to botany . Fig. 370.—Scouring-rush. A, male gametophyte or piothallus (152) show-ing antheridia (a, a). B-E, spermatozoids of various ages, muchmore highly magnified. (Hofmeister, Schacht.) Fig. 371.—Scouring-rush. Female gametophyte or prothallus (^1^-) showingarchegonia (a, a, a) and pseudo-roots (h). (Hofmeister.) in a cone-like aggregation of whorled sac-leaves. Each ofthese has a stalk ending in a shield-shaped expansion, six-sided from pressure. Behind each angle of the shield is alarge sporangium dehiscing by a longitudinal slit (3, 4)-The spores are peculiar in having four slender arms whichclose tightly about the spore when moist, and spread apartin drying, thus serving to eject the spores. They are there-fore called elaters (5, 6, 7). The massive, much-lobed gametophyte bearing gametangiaabove, and the comparatively large sessile sporangia of the scouring-rushes, indicate a closer kinship with the adder-tongues than withthe true ferns, and suggest that the Equisetince may have evol
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1913
