from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A supportive plant tissue that consists of thick-walled, usually lignified cells.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A mechanical, supportive ground tissue in plants consisting of aggregates of cells having thick, often mineralized walls
- n. The hard calcareous deposit in the tissues of Anthozoa, constituing the stony corals.
from the GNU version of the Collaborative International Dictionary of English
- n. Vegetable tissue composed of short cells with thickened or hardened walls, as in nutshells and the gritty parts of a pear. See sclerotic.
- n. The hard calcareous deposit in the tissues of Anthozoa, constituting the stony corals.
from The Century Dictionary and Cyclopedia
- n. The hard sub stance of the calcareous skeleton or corallum of sclerodermic corals, a proper tissue-secretion or calcification of the soft parts of the polyps themselves.
- n. In botany, the tissue largely composing the hard parts of plants, such as the shell (endocarp) of the hickory-nut, the seed-coat of seeds, the hypoderma of leaves, etc.
There is a broad well developed continuous band of sclerenchyma, which is connected at regular intervals with the epidermis by small vascular bundles.
The lower region usually forms a more or less clearly marked midrib, and consists of parenchymatous cells, some of which may contain oil-bodies or be differentiated as mucilage cells or sclerenchyma fibres.
An ordinary epidermal cell; st. stomata; sc. sclerenchyma; ph. phloen;
The other vascular bundles may have bands of sclerenchyma on both sides or on one side only or none.
The sclerenchyma lying on the lower side of the primary bundles are contiguous with the bundle, while those above are separated from the bundle by the chlorophyllous layer.
In the case of smaller bundles some are strengthened by sclerenchyma on the lower side and others have none.
But in the leaves of this grass, the development of sclerenchyma is not very considerable, but there is a great development of parenchymatous cells free from chlorophyll within the leaf, the chlorophyll bearing cells being confined to the upper and the lower surfaces of the leaves.
However, when we take into consideration the arrangement of bundles, the development and arrangement of sclerenchyma, every species of grass has its own special characteristics.
For example, in the leaves of _Panicum repens_ both the primary and secondary bundles are provided with sclerenchyma on both the sides, while those of the third order may have it on one side or not.
All the cells lying in the furrow between the motor-cells and the sclerenchyma are clear cells free from chlorophyll grains.