![]() ![]() Quite explicitly, definition 2 also includes a cylindrical coil spring and a strand of DNA, both of which are quite helical, so that "helix" is a more useful description than "spiral" for each of them in general, "spiral" is seldom applied if successive "loops" of a curve have the same diameter.A conical or volute spring (including the spring used to hold and make contact with the negative terminals of AA or AAA batteries in a battery box), and the vortex that is created when water is draining in a sink is often described as a spiral, or as a conical helix.The second definition includes two kinds of 3-dimensional relatives of spirals: In another example, the "center lines" of the arms of a spiral galaxy trace logarithmic spirals. ![]() The first definition describes a planar curve, that extends in both of the perpendicular directions within its plane the groove on one side of a gramophone record closely approximates a plane spiral (and it is by the finite width and depth of the groove, but not by the wider spacing between than within tracks, that it falls short of being a perfect example) note that successive loops differ in diameter. a three-dimensional curve that turns around an axis at a constant or continuously varying distance while moving parallel to the axis a helix.a curve on a plane that winds around a fixed center point at a continuously increasing or decreasing distance from the point.Two major definitions of "spiral" in the American Heritage Dictionary are: ![]() Helices An Archimedean spiral (black), a helix (green), and a conic spiral (red) It is a subtype of whorled patterns, a broad group that also includes concentric objects. In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point. Cutaway of a nautilus shell showing the chambers arranged in an approximately logarithmic spiral In cultivation in the UK this plant has gained the Royal Horticultural Society’s Award of Garden Merit.For other uses, see Spiral (disambiguation). The species is listed on Appendix I of CITES meaning commercial international trade is prohibited. In South Africa, it is a criminal offence to remove plants or seed of Aloe polyphylla from their natural habitat or to buy plants from roadside vendors. The species is highly sought after as an ornamental but is difficult to cultivate and usually soon dies if removed from its natural habitat. The region also has a very high summer rainfall and this moisture is augmented by the clouds which engulf the Lesotho mountain peaks. The climate is cool in the summer and in the winter the aloes are often covered in deep snow. Here it clings to rocky crevices and well-drained scree slopes. The spiral aloe grows in high, mountainous, grassy slopes at altitudes between 2,000 and 2,599 m (6,560 and 8,530 ft), and sometimes higher on east-facing slopes. This aloe flowers at the beginning of summer, producing flowers that range in colour from red to salmon pink and occasionally yellow, at the head of robust, branched inflorescences. The fat, wide, serrated, gray-green leaves have sharp, dark leaf-tips and grow in the five spiral rows. The plants do not seem to sucker or produce offshoots, but from the germination of their seeds they can form small, dense clumps. Description Spiral formed by leaves with emerging flower bud.Īloe polyphylla is a stemless aloe and grows its leaves in a very distinctive spiral shape which may be clockwise or anti-clockwise. Taxonomically, it forms part of the Rhodacanthae series of very closely related Aloe species, together with Aloe glauca, Aloe lineata and Aloe pratensis. ![]() The species epithet polyphylla means "many-leaved" in Greek. An evergreen succulent perennial, it is well known for its strikingly symmetrical, five-pointed spiral growth habit.Īloe polyphylla is commonly known as the spiral aloe in English, kroonaalwyn in Afrikaans, or lekhala kharetsa in Sesotho. Aloe polyphylla, the spiral aloe, kroonaalwyn, lekhala kharetsa, or many-leaved aloe, is a species of flowering plant in the genus Aloe that is endemic to the Kingdom of Lesotho in the Drakensberg mountains. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |