sunflower

The sunflower (Helianthus annuus) is an annual plant in the family Asteraceae and native to the Americas, with a large flowering head (inflorescence). The stem can grow as high as 3 meters (9.842ft), and the flower head can reach 30 cm (11.8 in) in diameter with the "large" seeds. The term "sunflower" is also used to refer to all plants of the genus Helianthus, many of which are perennial plants.

What is usually called the flower is actually a head (formally composite flower) of numerous florets (small flowers) crowded together. The outer florets are the sterile ray florets and can be yellow, maroon, orange, or other colors. The florets inside the circular head are called disc florets, which mature into what are traditionally called "sunflower seeds," but are actually the fruit (an achene) of the plant. The inedible husk is the wall of the fruit and the true seed lies within the kernel.

The florets within the sunflower's cluster are arranged in a spiraling pattern. Typically each floret is oriented toward the next by approximately the golden angle, 137.5°, producing a pattern of interconnecting spirals where the number of left spirals and the number of right spirals are successive Fibonacci numbers. Typically, there are 34 spirals in one direction and 55 in the other; on a very large sunflower there could be 89 in one direction and 144 in the other.

To grow well, sunflowers need full sun. They grow best in fertile, moist, well-drained soil with a lot of mulch. In commercial planting, seeds are planted 45 cm (1.5 ft) apart and 2.5 cm (1 in) deep.

Sunflower "whole seed" (fruit) are sold as a snack food, after roasting in ovens, with or without salt added. Sunflowers can be processed into a peanut butter alternative, Sunbutter. In Germany, it is mixed together with rye flour to make Sonnenblumenkernbrot (literally: sunflower whole seed bread), which is quite popular in German-speaking Europe. It is also sold as food for birds and can be used directly in cooking and salads.

Sunflower oil, extracted from the seeds, is used for cooking, as a carrier oil and to produce margarine and biodiesel, as it is cheaper than olive oil. A range of sunflower varieties exist with differing fatty acid compositions; some 'high oleic' types contain a higher level of healthy monounsaturated fats in their oil than even olive oil.

Detail of disk florets.

The cake remaining after the seeds have been processed for oil is used as a livestock feed. Some recently developed cultivars have drooping heads. These cultivars are less attractive to gardeners growing the flowers as ornamental plants, but appeal to farmers, because they reduce bird damage and losses from some plant diseases. Sunflowers also produce latex and are the subject of experiments to improve their suitability as an alternative crop for producing hypoallergenic rubber.

Traditionally, several Native American groups planted sunflowers on the north edges of their gardens as a "fourth sister" to the better known three sisters combination of corn, beans, and squash.^[6] Annual species are often planted for their allelopathic properties.^{[citation needed]}

However, for commercial farmers growing commodity crops, the sunflower, like any other unwanted plant, is often considered a weed. Especially in the midwestern USA, wild (perennial) species are often found in corn and soybean fields and can have a negative impact on yields.

Sunflowers may also be used to extract toxic ingredients from soil, such as lead, arsenic and uranium. They were used to remove uranium, cesium-137, and strontium-90 from soil after the Chernobyl accident (see phytoremediation).

source = http://en.wikipedia.org/wiki/Sunflower

Poinsettias (christmas flower)

Bright, flaming red, star-shaped Poinsettias are known as 'Flower of the Holy Night' or 'Flame Leaf' in the United States. One of the most popular flowers in Central America, it was brought here by Dr. Joel Poinsett, the first US ambassador to Mexico, over a hundred years ago. Still most of the supply of this famous beloved Christmas flower in American cities is said to come from California and the folklore attached to it comes from Mexico. Like Christmas Rose, this flower also represents the deep love for Christ and great devotion of a pure innocent human being to baby Jesus. However, in this instance, the devotees were two beautiful, naïve children who were not so fortunate as their friends to have enough money to do what their heart yearns for.

These poor children from Mexico were known as Maria, the sister and Pablo, her dear little brother. Just like all the other children in the village, they were looking forward to the Christmas festival and the annual Nativity play in which a large manger scene was set up in the village church. The season was full of parades and parties that were mainly centered around this church and all the people, especially children, used to gift presents to the baby child on Christmas Eve. Now, these two children loved Christ and the season of His birth very much but do not had any money to buy something for the baby Christ. They ardently wished to buy something special for the Christ but couldn't even buy the simplest of things for Him.

They were sad at heart and were quite disheartened by their poverty and misery when they set out for church to attend the service. They took the longer route in a vague hope to find dome blossoms to gift the child but couldn't find any. Finally, they picked up some wild weeds growing along the roadside as a gift for the Baby, squared their shoulders and approached the Church door. But how cruel little children can be, when they start teasing their fellow mates. Yet, Maria and Pablo braved their way to the manger and placed the greenery carefully around the manger. What happened next was the biggest surprise for all that were present! Bright red star-shaped flowers burst froth from the weeds and looked most sparkling of all gifts that the Christ child had received that day.

Euphorbia pulcherrima

Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Malpighiales Family: Euphorbiaceae Genus: Euphorbia Species: E. pulcherrima
Binomial name
Euphorbia pulcherrima Willd. ex Klotzsch

Commonly named poinsettia, is a species of flowering plant indigenous to Mexico and Guatemala. The name "poinsettia" is after Joel Roberts Poinsett, the first United States Minister to Mexico,^[1] who introduced the plant into the US in 1828.

n areas outside its natural environment it is commonly grown as an indoor plant where it prefers good morning sun then shade in the hotter part of the day. However, it is widely grown and very popular in subtropical climates such as Sydney, Australia.

As this is a subtropical plant, it will likely perish if the night-time temperature falls below 10°C (50°F) so is not suitable for planting in the ground in cooler climates. Likewise, daytime temperatures in excess of 21°C (70°F) tend to shorten the lifespan of the plant.^{[citation needed]}

The poinsettia is also cultivated in Egypt since 1860s, it was brought from Mexico during Egyptian campaign around 1860s. It is called "Bent El Consul", "the consul's daughter", referring to U.S. ambassador Mr. Poinsett.^{[citation needed]}

The poinsettia can be difficult to induce to reflower after the initial display when purchased. The plant requires a period of uninterrupted long, dark nights for around two months in autumn in order to develop flowers. Incidental light at night during this time will hamper flower production. When watering it is important to allow the plant to drain out any excess water. Having a poinsettia sit in water can do harm to the plant as it prefers moist soil to direct water.

In order to produce extra axillary buds that are necessary for plants containing multiple flowers, a phytoplasma infection – whose symptoms include the proliferation of axillary buds – is used.

Euphorbia albomarginata

The Rattlesnake Weed (Euphorbia albomarginata) is a low-growing member of the spurge family native to desert and chaparral habitats of southwestern North America, from southern California to Texas. This species is also known under the name of Whitemargin Sandmat.

Rattlesnake Weed is a common ground cover plant, usually growing less than 1/2 in (13 mm) high, with individual plants covering about a square foot, often growing closely and forming mats of vegetation. The flowers of this plant are tiny and edged in white, with a purplish center. Rattlesnake Weed can be found in open fields, on roadsides, or anywhere where the ground is disturbed, including ornamental gravels in suburban yards, where it is considered as a weed.

The name is derived from its former use as a folk remedy for snakebites (as a poultice or brewed as a tea) - however, this species is not proven to be medically effective in treating rattlesnake venom. Like most spurges, Rattlesnake Weed secretes an acrid, milky sap containing alkaloids poisonous to humans, with emetic and cathartic properties that may be misconstrued as curative.

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Rattlesnake Weed
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Subclass: Rosidae (unranked): Eurosids I Order: Malpighiales Family: Euphorbiaceae Subfamily: Euphorbioideae Tribe: Euphorbieae Subtribe: Euphorbiinae Genus: Euphorbia Species: E. albomarginata
Binomial name
Euphorbia albomarginata Torr. & Gray[verification needed]
Synonyms
Chamaesyce albomarginata

Euphorbia

The plants are annual or perennial herbs, woody shrubs or trees with a caustic, poisonous milky sap (latex). The roots are fine or thick and fleshy or tuberous. Many species are more or less succulent, thorny or unarmed. The main stem and mostly also the side arms of the succulent species are thick and fleshy, 15-91 cm (6-36 inches) tall. The deciduous leaves are opposite, alternate or in whorls. In succulent species the leaves are mostly small and short-lived. The stipules are mostly small, partly transformed into spines or glands, or missing.

Like all members of the family Euphorbiaceae, all spurges have unisexual flowers. In Euphorbia these are greatly reduced and grouped into pseudanthia called cyathia. The majority of species are monoecious (bearing male and female flowers on the same plant), although some are dioecious with male and female flowers occurring on different plants. It is not unusual for the central cyathia of a cyme to be purely male, and for lateral cyathia to carry both sexes. Sometimes young plants or those growing under unfavourable conditions are male only, and only produce female flowers in the cyathia with maturity or as growing conditions improve. The bracts are often leaf-like, sometimes brightly coloured and attractive, sometimes reduced to tiny scales. The fruits are three (rarely two) compartment capsules, sometimes fleshy but almost always ripening to a woody container that then splits open (explosively). The seeds are 4-angled, oval or spherical, and in some species have a caruncle.

Selected species

See List of Euphorbia species for complete list.

• Euphorbia albomarginata – Rattlesnake Weed, White-margined Sandmat
• Euphorbia amygdaloides – Wood Spurge
• Euphorbia antisyphilitica – Candelilla
• Euphorbia bulbispina
• Euphorbia cyparissias – Cypress Spurge
• Euphorbia decidua
• Euphorbia elastica – (Mexican) Palo Amarillo
• Euphorbia epithymoides – Cushion Spurge
• Euphorbia esula – Leafy Spurge
• Euphorbia franckiana
• Euphorbia helioscopia – Sun Spurge
• Euphorbia heterophylla – Painted Euphorbia, Desert Poinsettia, (Mexican) Fireplant, Paint Leaf, Kaliko
• Euphorbia labatii
• Euphorbia lactea – Mottled Spurge, Frilled Fan, Elkhorn
• Euphorbia lathyris – Caper Spurge, Paper Spurge, Gopher Spurge, Gopher Plant, Mole Plant
• Euphorbia maculata – Spotted Spurge, Prostrate Spurge
• Euphorbia maritae
• Euphorbia milii – Crown-of-thorns, Christ Plant
• Euphorbia myrsinites – Myrtle Spurge, Creeping Spurge, donkey tail
• Euphorbia paralias – Sea Spurge
• Euphorbia peplis – Purple Spurge
• Euphorbia peplus – Petty Spurge
• Euphorbia pulcherrima – Poinsettia, Mexican Flame Leaf, Christmas Star, Winter Rose, Noche Buena, Lalupatae, Pascua, Atatürk çiçeği (Turkish)
• Euphorbia resinifera – Resin Spurge
• Euphorbia serrata – Serrated spurge, Sawtooth spurge
• Euphorbia tirucalli – Indian Tree Spurge, Milk Bush, Pencil Tree
• Euphorbia tithymaloides – Devil's Backbone, "Redbird cactus", cimora misha (Peru)
• Euphorbia virosa

Anthurium

Anthurium grows in many forms, mostly evergreen, bushy or climbing epiphytes with roots that can hang from the canopy all the way to the floor of the rain forest. There are also many terrestrial forms which are found as understory plants, as well as hemiepiphytic forms. A hemiepiphyte is a plant capable of beginning life as a seed and sending roots to the soil, or beginning as a terrestrial plant that climbs a tree and then sends roots back to the soil. They occur also as lithophytes. Some are only found in association with arboreal ant colonies or growing on rocks in midstream (such as Anthurium amnicola).

The stems are short to elongate with a length between 15 and 30 cm. The simple leaves come in many shapes; most leaves are to be found at the end of the stems, although terrestrial plants show less of this pachycaul tendency. Leaves may be spatulate, rounded, or obtuse at the apex. They may be borne erect or spreading in a rosette, with a length that may surpass 100 cm in some of the larger species (such as Anthurium angamarcanum). The upper surface of the leaf may be matte, semiglossy, or fully glossy, and the leaf texture may range from leathery to fragile and papery. The leaves are petiolate and possess a structure called the geniculum, which is unique to the genus Anthurium. The geniculum allows the plant to swivel its leaves towards the sun, much in the same manner as sunflowers. In drier environments, the leaves can form a bird's-nest shaped rosette that enables the plant to collect falling debris, and thus water and natural fertilizer. Terrestrial growers or epiphytes often have cordate leaves; others grow as vines with rosettes of lanceolate leaves, and still others have many-lobed leaves.

Orchidaceae = Anggrek

Orchidaceae are well known for the many structural variations in their flowers.

Some orchids have single flowers but most have a racemose inflorescence, sometimes with a large number of flowers. The flowering stem can be basal, that is produced from the base of the tuber, like in Cymbidium, apical, meaning it grows from the apex of the main stem, like in Cattleya, or axillary, from the leaf axil, as in Vanda.

As an apomorphy of the clade, orchid flowers are primitively zygomorphic (bilaterally symmetrical), although in some genera like Mormodes, Ludisia, Macodes this kind of symmetry may be difficult to notice.

The orchid flower, like most flowers of monocots has two whorls of sterile elements. The outer whorl has three sepals and the inner whorl has three petals. The sepals are usually very similar to the petals (and thus called tepals, 1), but may be completely distinct.

The upper medial petal, called the labellum or lip (6),, is always modified and enlarged. The inferior ovary (7) or the pedicel usually rotates 180 degrees, so that the labellum, goes on the lower part of the flower, thus becoming suitable to form a platform for pollinators. This characteristic, called resupination occurs primitively in the family and is considered apomorphic (the torsion of the ovary is very evident from the picture). Some orchids have secondarily lost this resupination, e. g. Zygopetalum and Epidendrum secundum.

The normal form of the sepals can be found in Cattleya, where they form a triangle. In Paphiopedilum (Venus slippers) the lower two sepals are fused together into a synsepal, while the lip has taken the form of a slipper. In Masdevallia all the sepals are fused.

Orchid flowers with abnormal numbers of petals or lips are called peloric. Peloria is a genetic trait, but its expression is environmentally influenced and may appear random.

Longitudinal section of a flower of Vanilla planifolia

Orchid flowers primitively had three stamens, but this situation is now limited to the genus Neuwiedia. Apostasia and the Cypripedioideae have two stamens, the central one being sterile and reduced to a staminode. All of the other orchids, the clade called Monandria, retain only the central stamen, the others being reduced to staminodes (4). The filaments of the stamens are always adnate (fused) to the style to form cylindrical structure called the gynostemium or column (2). In the primitive Apostasioideae this fusion is only partial, in the Vanilloideae it is more deep, while in Orchidoideae and Epidendroideae it is total. The stigma (9) is very asymmetrical as all of its lobes are bent towards the centre of the flower and lay on the bottom of the column.

Pollen is released as single grains, like in most other plants, in the Apostasioideae, Cypripedioideae and Vanilloideae. In the other subfamilies, that comprise the great majority of orchids, the anther (3), carries and two pollinia.

A pollinium is a waxy mass of pollen grains held together by the glue-like alkaloid viscin, containing both cellulosic stands and mucopolysaccharides. Each pollinium is connected to a filament which can take the form of a caudicle, like in Dactylorhiza or Habenaria or a stipe, like in Vanda. Caudicles or stipes hold the pollinia to the viscidium, a sticky pad which sticks the pollinia to the body of pollinators.

At the upper edge of the stigma of single-anthered orchids, in front of the anther cap, there is the rostellum (5), a slender extension involved in the complex pollination mechanism.

As aforementioned, the ovary is always inferior (located behind the flower). It is three-carpelate and one or, more rarely, three-partitioned, with parietal placentation (axile in the Apostasioideae).

Pollination

Orchids have developed highly specialized pollination systems and thus the chances of being pollinated are often scarce. This is why orchid flowers usually remain receptive for very long periods and why most orchids deliver pollen in a single mass; each time pollination succeeds thousands of ovules can be fertilized.

Pollinators are often visually attracted by the shape and colours of the labellum. The flowers may produce attractive odours. Although absent in most species, nectar may be produced in a spur (8) of the labellum, on the point of the sepals or in the septa of the ovary, the most typical position amongst the Asparagales.

In orchids that produce pollinia, pollination happens as some variant of the following. When the pollinator enters into the flower, it touches a viscidium, which promptly sticks to its body, generally on the head or abdomen. While leaving the flower, it pulls the pollinium out of the anther, as it is connected to the viscidium by the caudicle or stipe. The caudicle then bends and the pollinium is moved forwards and downwards. When the pollinator enters another flower of the same species, the pollinium has taken such position that it will stick to the stigma of the second flower, just below the rostellum, pollinating it. The possessors of orchids may be able to reproduce the process with a pencil, small paintbrush, or other similar device.

Ophrys apifera is about to self-pollinate

Some orchids mainly or totally rely on self-pollination, especially in colder regions where pollinators are particularly rare. The caudicles may dry up if the flower hasn't been visited by any pollinator and the pollina then fall directly on the stigma. Otherwise the anther may rotate and then enter the stigma cavity of the flower (as in Holcoglossum amesianum).

The labellum of the Cypripedioideae is poke-shaped and has the function to trap visiting insects. The only exit leads to the anthers that deposit pollen on the visitor.

In some extremely specialized orchids, like the Eurasian genus Ophrys, the labellum is adapted to have a colour, shape and odour which attracts male insects via mimicry of a receptive female. Pollination happens as the insect attempts to mate with flowers.

Many neotropical orchids are pollinated by male orchid bees, which visit the flowers to gather volatile chemicals they require to synthesize pheromonal attractants. Each type of orchid places the pollinia on a different body part of a different species of bee, so as to enforce proper cross-pollination.

An underground orchid in Australia, Rhizanthella slateri, never sees the light of day and depends on ants and other terrestrial insects to pollinate it.

Catasetum, a genus discussed briefly by Darwin actually launches its viscid pollinia with explosive force when an insect touches a seta, knocking the pollinator off the flower.