Apocynaceae (/əˌpɑːsəˈneɪsiˌaɪ,-siːˌiː/, 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,[1] because some taxa were used as dog poison.[when?][2] Members of the family are native to the European, Asian, African, Australian, and American tropics or subtropics, with some temperate members.[1] 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, bleed clear sap without latex when damaged, and others, such as Pachypodium, have milky latex apart from their sap.
The dogbane/milkweed[2] family includes annual plants, perennial herbs, stem succulents, woody shrubs, trees, or vines.[1][3] Most exude a milky latex when cut.[4]
Leaves and stems
Leaves are simple. They may appear one at a time (singly) with each occurrence on alternating sides of the stem,[3] but usually occur in pairs (and rarely in whorls).[1] 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 finger-like.[3]
Inflorescence and fruit
Rhigospira quadrangularis, portion of a plant. 1) the inflorescence and 2) a flower, to scale; 3) corolla in bud, showing the pyramidal form of the erect segments in aestivation and 4) the same cut open when expanded, showing their simple sinistrorse convolution and the nearly basal position of the stamens, both magnified; 5) the calyx, disk, very short style, clavuncle, and stigmata, to scale; 6) the same, magnified; 7) a stamen, much magnified.[5]
Flowers have radial symmetry (actinomorphic),[1] and are borne in heads that are cymes or racemes, or are solitary in axils.[6] They are perfect (bisexual), with a synsepalous, five-lobed calyx united into a tube at the base.[1][6] Inflorescences are terminal or axillary. Five petals are united into a tube with four or five epipetalous stamens.[1] The style head is swollen.[7] The pollen is transported in foam.[7] The ovary is usually superior, bicarpellary, and apocarpous,[1] 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).[8]
The fruit is a drupe, a berry, a capsule, or a (frequently paired) follicle.[1] The seeds are often winged or have appendages of long silky hairs.[9]
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.[11]
An updated classification, including 366 genera, 25 tribes, and 49 subtribes, was published in 2014.[12]
Species in this family are distributed mainly in tropical regions:
In the tropical forests and swamps of Indomalaya: small to very tall evergreen trees up to 80 m (260 ft) tall, often with buttress roots, such as Alstonia and Dyera.
In Australia: occurs in all habitats; about 46 genera and about 200 species, including about 20 naturalised; herbs, vines, shrubs and trees.[14][15][16]
In Central America: Plumeria, or the frangipani, with its waxy white or pink flowers and a sweet scent.
In South America, Africa, and Madagascar: many lianas, such as Landolphia
In the Mediterranean region: Nerium, with the well-known oleander or be-still tree (Nerium oleander), and Apple of Sodom (Calotropis procera), with other (Calotropis) species extending into South Asia.
The only genera found in temperate Europe away from the Mediterranean are Vinca (Rauvolfioideae) and Vincetoxicum (Asclepiadoideae). Also Asclepias syriaca is an invasive weed (e. g., in many areas of Ukraine).
In North America: Apocynum, dogbane or Indian hemp, including Apocynum cannabinum, a traditional source of fiber. Also the bluestars, Amsonia, herbaceous perennials of upright habit, grown as ornamental plants for their attractive flowers.
In continental southern Africa (Angola, Botswana, Eswatini, Mozambique, South Africa, and Zimbabwe) and Madagascar, except for the humid evergreen forest of the eastern side of Madagascar, and never above 2,000 m (6,600 ft) for the entire island: Pachypodium and Fockea.
Ecology
Several genera are preferred larval host plants for the Queen Butterfly (Danaus gilippus).[17]
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,[6]Acokanthera,[18]Apocynum,[19]Thevetia,[20] 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)
There are limited dietary uses of plants from this family. The flower of Echites panduratus (common name: loroco) is edible.[40]Carissa (Natal plum) produces an edible fruit, but all other parts of the plant are poisonous.[41] The genus Apocynum was reportedly used as a source of fiber by Native Americans.[42] The aromatic fruit juice from Saba comorensis (syn. Landolphia comorensis, the Bungo or Mbungo fruit) is used as a drink.[43]
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.[24] The juice of Acokanthera species such as A. venenata and the milky juice of the NamibianPachypodium have been used as poison for arrow tips.[44]
Many species are ornamental in gardens or as houseplants.
^"Apocynaceae usually have copious latex and the leaves are often opposite and with colleters...", retrieved 3/10/18 from ANGIOSPERM PHYLOGENY WEBSITE, version 13http://www.mobot.org/MOBOT/Research/APweb/
^Nazia Nazar, David J. Goyder, James J. Clarkson, Tariq Mahmood and Mark W. Chase, 2013, "The taxonomy and systematics of Apocynaceae: Where we stand in 2012," Bot. J. Linn. Soc., 171(3, March), pp. 482–490, see [1], accessed 22 June 2015.
^Klots, Alexander B. (1951). A Field Guide to the Butterflies of North America, East of the Great Plains. Cambridge, Massachusetts: The Riverside Press. pp. 77–79.
^Zdrojewicz Z, Kuszczak B, Olszak N. (2016). "Ibogaina – budowa, wpływ na organizm człowieka, znaczenie kliniczne [Ibogaine - structure, influence on human body, clinical relevance]". Pol Merkur Lekarski. (in Polish). 41 (241): 50–55. PMID27734823.{{cite journal}}: CS1 maint: multiple names: authors list (link)
A review on antimicrobial botanicals, phytochemicals and natural resistance modifying agents from Apocynaceae family: Possible therapeutic approaches against multidrug resistance in pathogenic microorganisms. doi:10.1016/j.drup.2020.100695
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