. The anatomy of woody plants. Botany -- Anatomy. 346 THE ANATOMY OF WOODY PLANTS numerous, and bars of Sanio are clearly developed. The state- ment is often made that the ligneous structure of the Taxineae is free from parenchymatous elements (Fig. 252). This is certainly true of the mature wood of the stem in both Taxus and Torreya. If, however, the roots in the two genera be examined, a varying amount of storage parenchyma is discovered which is ordinarily better developed in proximity to the region of the primary wood (Fig. 253). In species common to Europe and America, namely, Taxus bacca
. The anatomy of woody plants. Botany -- Anatomy. 346 THE ANATOMY OF WOODY PLANTS numerous, and bars of Sanio are clearly developed. The state- ment is often made that the ligneous structure of the Taxineae is free from parenchymatous elements (Fig. 252). This is certainly true of the mature wood of the stem in both Taxus and Torreya. If, however, the roots in the two genera be examined, a varying amount of storage parenchyma is discovered which is ordinarily better developed in proximity to the region of the primary wood (Fig. 253). In species common to Europe and America, namely, Taxus baccata and its vari- eties, very little paren- chyma is found even in the root; but in oriental species of the genus storage ele- ments are somewhat abun- dant in this organ. The young stem, and particu- larly the root, of the genus Torreya show clearly developed longitudinal parenchyma in the wood. In CephalotaxuSy which by reason of the presence of a well-developed female cone at an early stage must be regarded as a primitive genus of the subtribe, parenchyma is markedly abundant in the organization of the wood. Injuries, also, frequently result in the recall of parenchyma in those taxineous woods which are normally without it. The generally uniseriate rays of the subtribe do not show the presence of traumatic ray- tracheids as a result of injury, and in this respect they present a marked resemblance to the woods of the Podocarpineae. Resin canals are conspicuously absent in the ligneous structures of the Taxineae, and not the slightest evidence of their former occurrence can be produced by experimental data. The genus Taxus is entirely without resin canals, even in its leaves, thus providing the only example of a conifer completely lacking these structures. An interesting parallel is presented by the hemlock (Tsuga) among. FIG. 252.—Transverse section of the wood of the stem in Taxus Please note that these images are extracted from scanned page images that may have
Size: 1576px × 1586px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookpublisherchicagoilltheuniversityo, booksubjectbotanyanatomy
