Limestone

Limestone (Lime) [ Geology ]

Dictionary of botanic terminology - index of names


	Limestone is a common sedimentary rock consisting mostly of the mineral calcite (calcium carbonate, CaCO₃)

The primary source of this calcite are the skeletons and shells of marine organisms. Secondary calcite may also be deposited by supersaturated waters such as stalagmites and stalactites. Limestone makes up approximately 10 percent of the total volume of all sedimentary rocks. Pure limestones are white or almost white. Because of impurities, such as clay, sand, organic remains, iron oxide and other materials, many limestones exhibit different colours, especially on weathered surfaces.

Soils reach in limestone (calcareous soils) are alkaline. The particular plants adapted to live in such a calcareous habitat are called calciophilous plant.

Many cactus and succulents are calciophilous and need some limestone grit/sand in the potting mix.

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994