. Handbook of grasses, treating of their structure, classification, geographical distribution and uses, also describing the British species and their habitats. Grasses. STEM AND INFLORESCENCE /' obtaining, with economy of material, the maximum of strength and resistance to lateral strains, inasmuch as the cylinder formed by the tissues of the culm has its wall radially graduated in strength —vital tissue consisting of soft parenchyma and fibrovascular bundles innermost; outside of this a cylinder of sclerenchyma, and at the periphery the silicified cells of the epidermis. The culms of some bam
. Handbook of grasses, treating of their structure, classification, geographical distribution and uses, also describing the British species and their habitats. Grasses. STEM AND INFLORESCENCE /' obtaining, with economy of material, the maximum of strength and resistance to lateral strains, inasmuch as the cylinder formed by the tissues of the culm has its wall radially graduated in strength —vital tissue consisting of soft parenchyma and fibrovascular bundles innermost; outside of this a cylinder of sclerenchyma, and at the periphery the silicified cells of the epidermis. The culms of some bamboos have their mechanical cells and epidermis so hard as to resist the blow of a hatchet. The closely investing leaf- sheaths give a great amount of support to the stem which would otherwise, in many cases, be unable to support its own weight. The immense saving of tissue, re- presented by the large central o cavity of the culms, enables them to grow with great rapidity; young bamboos have been observed to elongate 2-3 ft. in a day. A few grasses are exceptional in having the stems solid, the genera Glyceria and Sauharum. If we examine a transverse section of the stem of Saccharum officinarum, the Sugar-cane, we find that the fibrovascular bundles are most numerous near the circumference, the central part consisting mostly of parenchyma, among which the bundles are scattered sparsely. The flowers of grasses are en- veloped in small scales or bracts (glumes) which are imbricated or overlapped so as to form little spikes or clusters (spikelets). Thus in fig. 14 there are thirteen spike- lets represented; in fig. z6 there ^ ...... rfi 1 wnicn are emucuucu me lauiftLcu tiuiw- are ten spikelets. I hese glumes vascular bundles, oval shaped, showing are the distinguishing feature of the cavities (two wood-vessels), and exter- Glt,mace<,, a well-marked division L^^lfo^^^L'k'c^^ioS) rscl^^e^cSymt of the Monocotyledons, and com- s (mechanical cells), in which are em- prising,
Size: 2230px × 1120px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectgrasses, bookyear1910
