Begonia pavonina. Structural colour and iridescence in plants: the poorly studied relations of pigment colour. The bright colours of flowers attract pollinating insects by making the floral tissue stand out against a background of vegetation. Analyses of insect visual acuity have shown that vegetation is visually very similar to bark, soil and stone from an insect's point of view, because all these materials weakly reflect light across the whole range of the insect visual spectrum (Kevan et al., 1996). Flowers are different – they appear as bright colours because they selectively reflect certain wavelengths of light, which are perceptible to pollinating animals, and, usually, to humans as well. Colour is a property of both the coloured object and the perception of the animal observing it (Fig. 1).
Light arriving at an object can be transmitted through it, absorbed by it or reflected back from it. If an object reflects or transmits all wavelengths of light equally, then it is perceived as white (Fig. 1, top). Plants, like animals, achieve colour in two main ways. Plant iridescence. Untitled Document. Agrostis - Google 학술 검색. Lawn. San Francisco Botanical Garden Lawn A lawn is an area of land planted with grasses or (rarely) other durable plants, which are maintained at a short height and used for aesthetic and recreational purposes. Common characteristics of a lawn are that it is composed only of grass species, it is subject to weed and pest control, it is subject to practices aimed at maintaining its green color, and it is regularly mowed to ensure an acceptable length,[1] although these characteristics are not binding as a definition. In recreational contexts, the specialised names turf, pitch, field or green may be used, depending on the sport and the continent.
The term lawn, referring to a managed grass space, dates to no earlier than the 16th century. History[edit] Origins[edit] Before the invention of mowing machines in 1830, lawns were managed very differently. The English lawn[edit] Middle class pursuit[edit] This all changed with the invention of the lawnmower by Edwin Beard Budding in 1830. Poaceae. Grasslands such as savannah and prairie where grasses are dominant are estimated to constitute 40.5% of the land area of the Earth, excluding Greenland and Antarctica.[6] Grasses are also an important part of the vegetation in many other habitats, including wetlands, forests and tundra. The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize (corn), wheat, rice, barley, and millet as well as forage, building materials (bamboo, thatch, straw) and fuel (ethanol).
Etymology[edit] Evolutionary history[edit] Grasses include some of the most versatile plant life-forms. Prior to 2005, fossil findings indicated that grasses evolved around 55 million years ago. Description[edit] Diagram of a typical lawn grass plant. Growth and development[edit] Grass blades grow at the base of the blade and not from elongated stem tips. Distribution[edit] Ecology[edit] Taxonomy[edit] Uses[edit] Food production[edit] Industry[edit] Sports turf[edit] Poales. The earliest fossils attributed to the Poales date to the late Cretaceous period about 66 million years ago, though some studies (e.g., Bremer, 2002) suggest the origin of the group may extend to nearly 115 million years ago, likely in South America. The earliest known fossils include pollen and fruits. The flowers are typically small, enclosed by bracts, and arranged in inflorescences (except in the genus Mayaca, with solitary terminal flowers).
The flowers of many species are wind pollinated; the seeds usually contain starch. The APG III system (2009) accepts the order and places it in a clade called commelinids, in the monocots.[1] It uses this circumscription:[1] order Poales family Anarthriaceaefamily Bromeliaceaefamily Centrolepidaceaefamily Cyperaceaefamily Ecdeiocoleaceaefamily Eriocaulaceaefamily Flagellariaceaefamily Joinvilleaceaefamily Juncaceaefamily Mayacaceaefamily Poaceaefamily Rapateaceaefamily Restionaceaefamily Thurniaceaefamily Typhaceaefamily Xyridaceae Uses[edit]
Agrostis. Agrostis (bent or bentgrass) is a genus of over 100 species belonging to the grass family Poaceae,[1] commonly referred to as the bent grasses. Among this group are some of the main traditional lawn grasses. Selected species[edit] Uses[edit] Some species of bents are commonly used for lawn grass. Bentgrass is used in turf applications for its numerous advantages: it can be mowed to a very short length without damage, it can handle a great amount of foot traffic, it has a shallow root system that is thick and dense allowing it to be seeded and grow rather easily, and it has a pleasing, deep green appearance. Creeping Bent[edit] (Agrostis stolonifera) is the most commonly used species of Agrostis. Common Bent[edit] (Agrostis capillaris) was brought to America from Europe. Velvet Bent[edit] (Agrostis canina) gets it name for the velvet appearance that this grass produces.
Butterfly foodplant[edit] Butterflies whose caterpillars feed on Agrostis include: Zabulon Skipper, Poanes zabulon. Brachypodium. Brachypodium - Google 학술 검색.