Milkweed

Rubus Berry Plants

Milkweed

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Rubus Berry Plants

Rubus Berry Plants

Milkweed

Asclepias L. (1753), the Milkweed, is a Genus of herbaceous perennial, dicotyledonous Plants that contains over 140 known Species. It previously belonged to the Family Asclepiadaceae, but this is now classified as the subfamily Asclepiadoideae of the dogbane family Apocynaceae.

Milkweed is named for its milky juice, which contains alkaloids, latex, and several other complex compounds including cardenolides. Some species are known to be toxic.

Carl Linnaeus named the genus after Asclepius, the Greek god of healing, because of the many folk-medicinal uses for the Milkweed plants.

Pollination in this genus is accomplished in an unusual manner. Pollen is grouped into complex structures called pollinia (or "pollen sacs"), rather than being individual grains or tetrads, as is typical for most plants. The feet or mouthparts of Flower visiting insects such as bees, wasps and butterflies, slip into one of the five slits in each flower formed by adjacent anthers. The bases of the pollinia then mechanically attach to the insect, pulling a pair of pollen sacs free when the pollinator flies off. Pollination is effected by the reverse procedure in which one of the pollinia becomes trapped within the anther slit.

Asclepias species produce their Seeds in follicles. The seeds, which are arranged in overlapping rows, have white silky filament-like hairs known as pappus, silk, or floss. The follicles ripen and split open and the seeds, each carried by several dried pappus, are blown by the wind.

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Family

Rubus Berry Plants

Family

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Rubus Berry Plants

Rubus Berry Plants

Family

In biological classification, family (Latin: familia) is

* a taxonomic rank. Other well-known ranks are Life, Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the prefix sub-: subfamily (Latin: subfamilia).
* a taxonomic unit, a taxon, in that rank. In that case the plural is families (Latin familiae)

Example: Walnuts and hickories belong to the Juglandaceae, or walnut family.

What does and does not belong to each family is determined by a taxonomist. Similarly for the question if a particular family should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing a family. Some taxa are accepted almost universally, while others are recognised only rarely.

History of the concept

Family, as a rank intermediate between order and genus, is a relatively recent invention.

The taxonomic term familia was first used by French botanist Pierre Magnol in his Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur (1689) where he called the seventy-six groups of plants he recognised in his tables families (familiae). The concept of rank at that time was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera, which is far from how the term is used today.

Carolus Linnaeus used the word familia in his Philosophia botanica (1751) to denote major groups of plants: trees, herbs, ferns, palms, and so on. He used this term only in the morphological section of the book, discussing the vegetative and generative organs of plants. Subsequently, in French botanical publications, from Michel Adanson's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille was used as a French equivalent of the Latin ordo (or ordo naturalis). In nineteenth century works such as the Prodromus of Augustin Pyramus de Candolle and the Genera Plantarum of George Bentham and Joseph Dalton Hooker this word ordo was used for what now is given the rank of family.

In zoology, the family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes, disposés dans un ordre naturel (1796). He used families (some of them not named) in some but not in all his orders of "insects" (which then included all arthropods).

Since the beginning of the 20th century, however, the term has been consistently used in its modern sense. Its usage and characteristic ending of the names belonging to this category are governed by the various nomenclature codes. These are "-idae" in the zoological code, and "-aceae" in the botanical and bacteriological codes.

Uses

families may be used for evolutionary and palaeontological studies because they are more stable then lower taxonomic levels such as genera and species.

Related : Rubus
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Related : Family From Wikipedia, the free encyclopedia, Rubus Berry Plants

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