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Cinnabar is the more stable form, and is a structure akin to that of HgO: each Hg center has two short Hg−S bonds (each 2.36 Å), and four longer Hg···S contacts (with 3.10, 3.10, 3.30 and 3.30 Å separations). In addition, HgS is found in a black, non-cinnabar polymorph (metacinnabar) that has the zincblende structure. [5]
The dragon blood tree has an upturned, densely packed crown. This evergreen species is named after its dark red resin, which is known as "dragon's blood". Unlike most monocot plants, Dracaena displays secondary growth, D. cinnabari even has growth zones resembling tree rings found in dicot tree species.
Parenchyma is a versatile ground tissue that generally constitutes the "filler" tissue in soft parts of plants. It forms, among other things, the cortex (outer region) and pith (central region) of stems, the cortex of roots, the mesophyll of leaves, the pulp of fruits, and the endosperm of seeds.
[1] [6] The flower stem is known as a pedicel, and those flowers with such a stem are called pedicellate, while those without are called sessile. [7] In the angiosperms, the flowers are arranged on a flower stem as an inflorescence. Just beneath (subtended) the flower there may be a modified, and usually reduced, leaf, called a bract.
At the meristem summit, there is a small group of slowly dividing cells, which is commonly called the central zone. Cells of this zone have a stem cell function and are essential for meristem maintenance. The proliferation and growth rates at the meristem summit usually differ considerably from those at the periphery.
It is normally found in stems, leaves, and tips of stems and roots and consists of undifferentiated cells that are constantly dividing allowing for plant growth and give rise to plant tissue systems. The meristem tissue's ability to continuously divide allows for vegetative propagation to occur.
Statoliths are dense amyloplasts, organelles that synthesize and store starch involved in the perception of gravity by the plant (gravitropism), that collect in specialized cells called statocytes. Statocytes are located in the starch parenchyma cells near vascular tissues in the shoots and in the columella in the caps of the roots. [15]
Prickles on a blackberry branch. In plant morphology, thorns, spines, and prickles, and in general spinose structures (sometimes called spinose teeth or spinose apical processes), are hard, rigid extensions or modifications of leaves, roots, stems, or buds with sharp, stiff ends, and generally serve the same function: physically defending plants against herbivory.