Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
The tree ferns are the ferns that grow with a trunk elevating the fronds above ground level, making them trees. Most tree ferns are members of the "core tree ferns", belonging to the families Dicksoniaceae, Metaxyaceae, and Cibotiaceae in the order Cyatheales. This order is the third group of ferns known to have given rise to tree-like forms. Others tree ferns include the extinct Psaroniaceae, which are members of Marattiales, some members of Osmundaceae and the extinct Guaireaceae within the Osmundales, and the extinct Tempskya of uncertain position.
Keratinocytes are the primary type of cell found in the epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. Basal cells in the basal layer of the skin are sometimes referred to as basal keratinocytes. Keratinocytes form a barrier against environmental damage by heat, UV radiation, water loss, pathogenic bacteria, fungi, parasites, and viruses. A number of structural proteins, enzymes, lipids, and antimicrobial peptides contribute to maintain the important barrier function of the skin. Keratinocytes differentiate from epidermal stem cells in the lower part of the epidermis and migrate towards the surface, finally becoming corneocytes and eventually be shed off, which happens every 40-56 days in humans.
Trichomes, from the Greek τρίχωμα (trichōma) meaning "hair", are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant is an indumentum, and the surface bearing them is said to be pubescent.
Roridula is a genus of evergreen, insect-trapping shrubs, with two species, of about 1⅓–2 m. It is the only genus in the family Roridulaceae. It has thin, woody, shyly branching, upright, initially brown, later grey stems, with lance- to awl-shaped leaves crowded at their tips. The star-symmetrical flowers consist from the outside in of five, green or reddish, free sepals, alternating with five white, pink or purple, free petals. Further to the middle and opposite the sepals are five stamens with the anthers initially kinked down. These suddenly flip up if the nectar-containing swelling at its base is being touched. The center of the flower is occupied by a superior ovary. The leaves and sepals carry many sticky tentacles of different sizes, that trap insects. Roridula does not break down the insect proteins, but bugs of the genus Pameridea prey on the trapped insects. These later deposit their feces on the leaves, which take up nutrients from the droppings. The species can be found in the Western Cape province of South Africa. They are commonly known as dewstick or fly bush in English and vlieëbos or vlieëbossie in Afrikaans.
The epidermis is a single layer of cells that covers the leaves, flowers, roots and stems of plants. It forms a boundary between the plant and the external environment. The epidermis serves several functions: it protects against water loss, regulate gas exchange, secretes metabolic compounds, and absorbs water and mineral nutrients. The epidermis of most leaves shows dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. Woody stems and some other stem structures such as potato tubers produce a secondary covering called the periderm that replaces the epidermis as the protective covering.
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs it is primarily seen in snails and clams, i.e. in gastropods and bivalves, but it is also found in cephalopods such as Allonautilus scrobiculatus. The periostracum is an integral part of the shell, and it forms as the shell forms, along with the other shell layers. The periostracum is used to protect the organism from corrosion.
Delosperma is a genus of around 100 species of succulent plants, formerly included in Mesembryanthemum in the family Aizoaceae. It was defined by English botanist N. E. Brown in 1925. The genus is common in southern and eastern Africa. Delosperma species, as do most Aizoaceae, have hygrochastic capsules, opening and closing as they wet and dry.
This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens. This page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is also an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, and organized by plant anatomy and function in plant physiology.
This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology and List of Latin and Greek words commonly used in systematic names.
A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, stores nutrients, and produces new living tissue.
A leaf is the principal lateral appendage of the vascular plant stem, usually borne above ground and specialized for photosynthesis. The leaves, stem, flower and fruit together form the shoot system. Leaves are collectively referred to as foliage, as in "autumn foliage". In most leaves, the primary photosynthetic tissue, the palisade mesophyll, is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of Eucalyptus, palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper and lower surfaces that differ in color, hairiness, the number of stomata, the amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll that is essential for photosynthesis as it absorbs light energy from the sun. A leaf with lighter-colored or white patches or edges is called a variegated leaf.
Trichodiadema bulbosum is a succulent plant of the genus Trichodiadema, native to South Africa.
Trichodiadema marlothii is succulent plant of the genus Trichodiadema, native to the Western Cape Province, South Africa, where it is known from the Robertson and Swellendam areas.
Trichodiadema burgeri is succulent plant of the genus Trichodiadema, native to the Western Cape Province, South Africa, where it is known from the Montagu and Oudtshoorn regions.
Trichodiadema calvatum is succulent plant of the genus Trichodiadema, native to the Western Cape Province, South Africa, where it is found in shales, in open rocky areas within Renosterveld vegetation.
Trichodiadema occidentale is succulent plant of the genus Trichodiadema, native to the Western Cape Province, South Africa, where it grows in rocky shale or limestone hills in the Overberg region, and especially in disturbed areas.
Trichodiadema pygmaeum is succulent plant of the genus Trichodiadema, native to the Western Cape Province, South Africa, where it is found in fine-grained soils in the regions of Bredasdorp and Swellendam.
Trichodiadema hallii is succulent plant of the genus Trichodiadema, native to the Ladismith area of the Western Cape Province, South Africa.
Trichodiadema barbatum is succulent plant of the genus Trichodiadema, native to the Western Cape Province, South Africa. It has gained the Royal Horticultural Society's Award of Garden Merit.
