Apocynaceae
Apocynaceae (from "Apocynum", Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison. Members of the family are native to the European, Asian, African, Australian, and American tropics or subtropics, with some temperate members. The former family Asclepiadaceae (now known as Asclepiadoideae) is considered a subfamily of Apocynaceae and contains 348 genera. A list of Apocynaceae genera may be found here. Many species are tall trees found in tropical forests, but some grow in tropical dry  (xeric) environments. Also perennial herbs from temperate zones occur. Many of these plants have milky latex, and many species are poisonous if ingested, the family being rich in genera containing alkaloids and cardiac glycosides, those containing the latter often finding use as arrow poisons. Some genera of Apocynaceae, such as "Adenium", have milky latex apart from their sap, and others, such as "Pachypodium", have clear sap and no latex. Taxonomy. As of 2012, the family was described as comprising some 5,100 species, in five subfamilies: The former family Asclepiadaceae is included in Apocynaceae according to the Angiosperm Phylogeny Group III  (APG III) modern, largely molecular-based system of flowering plant taxonomy. An updated classification, including 366 genera, 25 tribes and 49 subtribes, was published in 2014. Distribution and habitat. Species in this family are distributed mainly in tropical regions: Description. Growth pattern. The dogbane/milkweed family includes annual plants, perennial herbs, stem succulents, woody shrubs, trees, or vines. Most exude a milky latex when cut. Leaves and stems. Leaves are simple. They may appear one at a time (singly) with each occurrence on alternating sides of the stem (alternate), but usually occur in pairs (and rarely in whorls). When paired , they occur on opposite sides of the stem (opposite), with each pair occurring at an angle rotated 90° to the pair below it (decussate). There is no stipule (a small leaf-like structure at the base of the leaf stem), or stipules are small and sometimes fingerlike. Inflorescence and fruit. Flowers have radial symmetry (actinomorphic), and are borne in heads that are cymes or racemes, or are solitary in axils. They are perfect (bisexual), with a synsepalous, five-lobed calyx united into a tube at the base. Inflorescences are terminal or axillary. Five petals are united into a tube  with four or five epipetalous stamens. The style head is swollen. The pollen is transported in foam. The ovary is usually superior, "bicarpellary," and "apocarpous," with a common fused style and stigma. (Fig. 5. and Fig.6. in the illustration of "Rhigospira quadrangularis" show a typical tripartite style which divides into three zones (specialised for pollen deposition, viscin secretion, and the reception of pollen) The fruit is a drupe, a berry, a capsule, or a follicle. The seeds are often winged or have appendages of long silky hairs. Ecology. Several genera are preferred larval host plants for the Queen Butterfly ("Danaus  gilippus"). Toxicity. Many species of plants from the family Apocynaceae have some toxicity, with some being extremely poisonous if parts are ingested, or if they are not handled properly. Genera containing cardiac glycosides— "Cerbera", "Nerium", "Asclepias", "Cascabela", "Strophanthus," "Acokanthera", "Apocynum," "Thevetia," etc.—have therapeutic ranges, but are often associated with accidental poisonings, in many cases lethal (see below). Alkaloid-producing species like "Rauvolfia serpentina," "Catharanthus roseus," and "Tabernanthe iboga" are likewise the source of compounds with therapeutic ranges, but which have significant associated toxicities if not taken in appropriate doses and in controlled fashion. (See below) Uses. Several members of the  family Apocynaceae have had economic uses in the past. Several are sources of important natural products—pharmacologic tool compounds and drug research candidates, and in some cases actual prescription drugs. Cardiac glycosides, which affect heart function, are a ready example. Genera studied and known to contain such glycosides include "Acokanthera", "Apocynum", "Cerbera", "Nerium", "Thevetia" and "Strophanthus." "Rauvolfia serpentina" (Indian snakeroot) contains the alkaloid reserpine, which has been used as an antihypertensive and an antipsychotic drug but its adverse effects limit its clinical use. "Catharanthus roseus" yields alkaloids used in the treatment of cancer. "Tabernanthe iboga, Voacanga africana, and Tabernaemontana undulata  contain the alkaloid ibogaine, which is a psychedelic drug which may help with drug addiction, but which has significant adverse effects, with ibogaine being both cardiotoxic and neurotoxic. Ajmalicine, an alkaloid found in Rauvolfia" spp., "Catharanthus roseus", and "Mitragyna speciosa", is an antihypertensive drug used in the treatment of high blood pressure. Many genera are grown as ornamental plants, including "Amsonia" (bluestar), "Nerium" (oleander), "Vinca" (periwinkle), "Carissa" (Natal plum), "Allamanda" (golden trumpet), "Plumeria" (frangipani), "Thevetia", "Mandevilla" (Savannah flower), and "Adenium" (desert-rose). In addition, the genera "Landolphia", "Carpodinus",and "Mascarenhasia" have been used as commercial sources of inferior rubber. (See Congo  rubber). There are limited dietary uses of plants from this family. The flower of "Fernaldia pandurata" (common name: "") is edible. "Carissa" (Natal plum) produces an edible fruit, but all other parts of the plant are poisonous. The genus "Apocynum" was reportedly used as a source of fiber by Native Americans. The aromatic fruit juice from "Saba comorensis" (syn. "Landolphia comorensis", the Bungo or Mbungo fruit) is used as a drink. Finally, ethnopharmacologic and ethnotoxicologic uses are also known. The roots of "Tabernanthe iboga" and certain "Voacanga" species have traditionally been used ceremonially as hallucinogens in Africa. The ibogaine-type alkaloids  responsible for the psychoactivity of these plants have been studied with regard to the treatment of drug addiction. The juice of "Acokanthera" species such as "A. venenata" and the milky juice of the Namibian "Pachypodium" have been used as poison for arrow tips.