The structure & development of the mosses and ferns (Archegoniatae) . ids near thefoci of the elliptical sec-tion. From here theformation proceeds to-wards the centre, and inthe full-grown root thetracheary tissue forms acontinuous band occupy-ing the larger axis ofthe section, the last-formed tracheids beingthe largest. On eitherside of this trachearyplate is a poorly de-fined mass of phloem,similar to that of thestem and leaf also no bundle- FiG. iig.—Vascular bundle of the root of C/^«(^?i:/z«;z, X85. shcath IS prCSCnt and the limits of the bundleare not clearly defined. In O.
The structure & development of the mosses and ferns (Archegoniatae) . ids near thefoci of the elliptical sec-tion. From here theformation proceeds to-wards the centre, and inthe full-grown root thetracheary tissue forms acontinuous band occupy-ing the larger axis ofthe section, the last-formed tracheids beingthe largest. On eitherside of this trachearyplate is a poorly de-fined mass of phloem,similar to that of thestem and leaf also no bundle- FiG. iig.—Vascular bundle of the root of C/^«(^?i:/z«;z, X85. shcath IS prCSCnt and the limits of the bundleare not clearly defined. In O. vulgatum the bundle of the rootis diarch to begin with, but by the suppression of one of thephloem masses it becomes monarch. The development of the sporangium has been studied byGoebel ^ in O. vulgatum, and recently by Bower ^ in this speciesand in 0. penduhcm. The latter has been carefully examinedby the writer, and the results confirm that of the latter investi-gator, except that it seems possible that the archesporium may1 Goebel (17), p. 390. ^ Bower (14).. VIII THE PTERIDOPHVTA — OPHIOGLOSSACE^ -2>7 be traced to a single cell, as Goebel asserts is probably the casein O. vulgatum. A transverse section of the very young sporangiophore issomewhat triangular, the broader side corresponding to theouter surface of the sporangiophore. The cells are very irre-gular in form, and no differentiation of the tissues is to beobserved. Sections of somewhat older stages show in somecases, at least, a large epidermal cell occupying nearly thecentre of the shorter sides of the triangular section. This cellhas a larger nucleus than its neighbours, and is decidedly broader. B,
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Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895
