The roots of _Lyginodendron_, when young, were like those of the Marattiaceous ferns, their five-rayed mass of wood being characteristic of that family, and different from the type of root found in most other ferns (cf. fig. 78B with fig. 35 on p. 60). Unlike fern roots of any kind, however, they have well-developed zones of secondary wood, in which they approach the Gymnospermic roots (see fig. 78B, _s_). [Illustration: Fig. 78B.—Transverse Section of Root of _Lyginodendron_ _w_, Five-rayed mass of primary wood; _s_, zone of secondary wood; _c_, cortical and other soft tissues.] A further mixture of characters is seen in the vascular bundles of the petioles. A double strand, like that in the lower Gymnosperms, goes off to the leaf base from the main axis, but in the petiole itself the bundle is like a normal fern stele, and shows no characters in transverse section which would separate it from the ferns. Such a petiole is illustrated in fig. 79, with its V-shaped fernlike stele. On the petioles and stems were certain rough, spiny structures of the nature of complex hairs. In some cases they are glandular, as is seen in _g_ in fig. 79, and as they seem to be unique in their appearance they have been of great service in the identification of the various isolated organs of the plant. As is seen from fig. 77, the leaves were quite fern-like, but in structural specimens they have been found with the characteristic glandular hairs of the plant. The seeds were so long known under the name of _Lagenostoma_ that they are still called by it, though they have been identified as belonging to _Lyginodendron_. They were small (about ¼ in. in maximum length) when compared with those of most other plants of the group, or of the Cycads, with which they show considerable affinity. They are too complex to describe fully, and have been mentioned already (see p. 76), so that they will not be described in much detail here. The diagrammatic figure (fig. 56) shows the essential characters of their longitudinal section, and their transverse section, as illustrated in fig. 80, shows the complex and elaborate mechanism of the apex. [Illustration: Fig. 79.—Transverse Section through Petiole of _Lyginodendron_ _v_, Fern-like stele; _c_, cortex; _g_, glandular hairlike protuberances.] Round the “seed” was a sheath, something like the husk round a hazel nut, which appears to have had the function of a protective organ, though what its real morphological nature may have been is as yet an unsolved problem. On the sheath were glandular hairs like those found on the petiole and leaves, which were, indeed, the first clues that led to the discovery of the connection between the seed and the plant _Lyginodendron_.