A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek word κάκτος (káktos), a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. Although some species live in quite humid environments, most cacti live in habitats subject to at least some drought. Many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on Earth. Because of this, cacti show many adaptations to conserve water. For example, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of true leaves, cacti's enlarged stems carry out photosynthesis. Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka.
Rooibos, Aspalathus linearis, is a broom-like member of the plant family Fabaceae that grows in South Africa's fynbos biome.
Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaves, short internodes and leaf orientation which is parallel or oblique to direct sunlight. The word comes from the Greek sklēros (hard) and phyllon (leaf). The term was coined by A.F.W. Schimper in 1898, originally as a synonym of xeromorph, but the two words were later differentiated.
Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or female. Cycads vary in size from having trunks only a few centimeters to several meters tall. They typically grow very slowly and live very long. Because of their superficial resemblance, they are sometimes mistaken for palms or ferns, but they are not closely related to either group.
Glossopteris [etymology: from Ancient Greek γλῶσσα + πτερίς ] is the largest and best-known genus of the extinct Permian order of seed ferns known as Glossopteridales. The genus Glossopteris refers only to leaves, within a framework of form genera used in paleobotany. Species of Glossopteris were the dominant trees of the middle- to high-latitude lowland vegetation across the supercontinent Gondwana during the Permian Period. Glossopteris fossils were critical in recognizing former connections between the various fragments of Gondwana: South America, Africa, India, Australia, New Zealand, and Antarctica.
Gasteria is a genus of succulent plants, native to South Africa.
The Proteaceae form a family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genera with about 1,660 known species. Together with the Platanaceae and Nelumbonaceae, they make up the order Proteales. Well-known genera include Protea, Banksia, Embothrium, Grevillea, Hakea and Macadamia. Species such as the New South Wales waratah, king protea, and various species of Banksia, soman, and Leucadendron are popular cut flowers. The nuts of Macadamia integrifolia are widely grown commercially and consumed, as are those of Gevuina avellana on a smaller scale. Australia and South Africa have the greatest concentrations of diversity.
William Brian Keith Holmes is an Australian palaeobotanist, best known for his work "Fructifications of Glossopteris" (1974), published in the Proceedings of the Linnean Society of New South Wales. Despite having received no formal training in palaeontology, he has become an important contributor in the field and has described some 80 new species, mostly from 2 quarries at Nymboida in northern New South Wales, and situated on the Triassic.
The Molteno Formation is a geological formation found in several localities in Lesotho and South Africa. It lies mainly south of Maseru, near Burgersdorp, Aliwal North, Dordrecht, Molteno, and Elliot. It extends as far north as Matatiele in the Eastern Cape. The formation's localities lie along the Drakensberg Mountains in Kwazulu-Natal, and near Ladybrand in the Free State of South Africa. The Molteno Formation is the lowermost of the three formations in the Stormberg Group of the greater Karoo Supergroup. The Molteno Formation represents the initial phase of preserved sedimentation of the Stormberg Group.
In plant morphology, thorns, spines, and prickles, and in general spinose structures, are hard, rigid extensions or modifications of leaves, roots, stems or buds with sharp, stiff ends, and generally serve the same function: physically deterring animals from eating the plant material.
Dicroidium is an extinct genus of fork-leaved seed ferns that were widely distributed over Gondwana during the Triassic. Their fossils are known from South Africa, the Arabian Peninsula, Australia, New Zealand, South America, Madagascar, the Indian subcontinent and Antarctica. They were first discovered in Triassic sediments of Tasmania by Morris in 1845. Fossils from the Umm Irna Formation in Jordan and in Pakistan indicate that these plants already existed in Late Permian. Late surviving members of the genus are known from the Early Jurassic (Sinemurian) of East Antarctica. Within paleobotany, Dicroidium is a form genus used to refers to the leaves, associated with ovuluate organs classified as Umkomasia and pollen organs classified as Pteruchus, while Dicroidum is also used collectively to refer to the whole plant.
Umkomasia is a genus of seed bearing organs produced by corystosperm seed ferns, first based on fossils collected by Hamshaw Thomas from the Burnera Waterfall locality near the Umkomaas River of South Africa. He recognized on the basis of cuticular similarities that the same plant produced pollen organs Pteruchus and the leaves Dicroidium. Various other corystosperm seed bearing organs from the Jurassic and Cretaceous have been assigned to this genus, but recently have been given distinct genera, with Umkomasia being restricted to the Triassic.
Umkomasia macleanii is an ovulate structure of a seed fern (Pteridospermatophyta and the nominate genus of Family Umkomasiaceae. It was first described by Hamshaw Thomas from the Umkomaas locality of South Africa.
Pteruchus africanus is a pollen organ of a seed fern (Pteridospermatophyta). It was first described by Hamshaw Thomas from the Umkomaas locality of South Africa.
Umkomasia feistmantelii is an unusually large species of Umkomasia from the Early Triassic of New South Wales, Australia.
Dicroidium zuberi is a large bipinnate species of the seed fern Dicroidium with a forked rachis. The leaves are affiliated with Umkomasia feistmantellii megasporophylls and Petruchusbarrealensis microsporophylls.
Pteruchus is a form genus for pollen organs of the seed fern (Pteridospermatophyta family Umkomasiaceae. It was first described by Hamshaw Thomas from the Umkomaas locality of South Africa. It is associated with the seed bearing organs Umkomasia and Dicroidium leaves.
Corystospermaceae is a natural family of seed ferns (Pteridospermatophyta) also called Umkomasiaceae, and first based on fossils collected by Hamshaw Thomas from the Burnera Waterfall locality near the Umkomaas River of South Africa The leaves of Dicroidium were recognized by Alex Du Toit to unite all the countries of the Gondwana supercontinent during the Triassic: Africa, South America, India, and Australia. Subsequently, Dicroidium was found in the Triassic of Antarctica and New Zealand, and also the Permian Umm Irna Formation of Jordan. According to the form generic system of paleobotany, leaves are given separate generic names to ovulate and pollen organs, but the discovery of these reproductive organs in Africa by Thomas, and subsequently throughout Gondwana, strengthened Du Toit's concept of a continuous southern supercontinent. Corystospermaceae were also components of Jurassic and Cretaceous floras, declining in the Cretaceous presumably due to the rise of flowering plants, the last known representative of the group, Komlopteris cenozoicus, is known from the Eocene of Tasmania, at least 13 million years after the Cretaceous–Paleogene extinction event.
Santa Juana Formation a Late Triassic sedimentary rock formation near Santa Juana in the lower course of the Biobío River in south-central Chile. Lithologies range from conglomerate sandstone, arkosic sandstone, siltstone and mudstone.
The Paso Flores Formation is a latest Late Triassic (Rhaetian) geologic formation in the Neuquén Basin of Neuquén Province in northwestern Patagonia, Argentina. The brown to red-stained conglomerates, sandstones and shales of the formation represent the youngest and only latest Triassic sedimentary unit in the country, overlying basement.
