Apocynaceae

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Apocynaceae
Apocynum cannabinum 5.jpg
Apocynum cannabinum
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Gentianales
Family: Apocynaceae
Juss.
Type genus
Apocynum
L.
Synonyms

Apocynaceae is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly called the dogbane family,[1] after the American plant known as dogbane, Apocynum cannabinum.[2] Members of the family are native to European, Asian, African, Australian, and American tropics or subtropics, with some temperate members.[1]

Many species are tall trees found in tropical rainforests, 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. 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.

Description[edit]

Alstonia scholaris, arrangement of leaves

Growth pattern[edit]

The dogbane family includes annual plants, perrenial herbs, stem succulents, woody shrubs, trees, or vines.[3][1] Most[citation needed] exude a milky sap with latex[citation needed], if injured.

Leaves and stems[edit]

Leaves are not divided into smaller leaflets (simple). Leaves may appear one at a time (singly) with each occurrence on alternating sides of the stem (alternate),[3] but usually[citation needed] occur in pairs or 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.[3]

Inflorescence and fruit[edit]

Flowers are usually[citation needed] showy, have radial symmetry (actinomorphic), and are born in head that are cymes or racemes, but can rarely be fasciculate or solitary. 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 is expanded at the apex into a massive clavuncle just below the stigma. The ovary is usually superior, bicarpellary, and apocarpous, with a common fused style and stigma.

The fruit is a drupe, a berry, a capsule, or a follicle.

Taxonomy[edit]

The family comprises some 1,500 species divided over about 424 genera. Apocynoideae, Asclepiadoideae, Periplocoideae, Rauvolfioideae, and Secamonoideae are the 5 subfamilies of Apocynpidea as of 2012.[4] What is included in the family may change with new genetic data. The former family Asclepiadaceae is included in Apocynaceae according to the APG III system.[5]

Distribution and habitat[edit]

Species in this family are distributed mainly in tropical regions:

Ecology[edit]

Several genera are preferred larval host plants for the Queen Butterfly (Danaus gilippus). [6]

Uses[edit]

Vinca major, a popular garden plant

Several plants of this family had economic uses in the past.

The genera Landolphia, Hancornia, Funtumia and Mascarenhasia were used as a commercial source of inferior rubber. (see Congo rubber, made largely from various Landolphia harvested from the wild under the most desperate conditions)

The juice of Acokanthera species such as A. venenata and the milky juice of the Namibian Pachypodium has been used as venom for arrow tips by the San (Bushmen). Some sources state that Pachypodium do not produce a milky latex.[7]

Several genera are grown as ornamental plants, including Amsonia (bluestar), Nerium (oleander), Vinca (periwinkle), Carissa (Natal plum, an edible fruit), Allamanda (golden trumpet), Plumeria (frangipani), Thevetia (lucky nut), Mandevilla (Savannah flower), Adenium (desert-rose).

Some are sources of important drugs, such as cardiac glycosides, which affect heart function. These include the Acokanthera, Apocynum, Cerbera, Nerium, Thevetia and Strophantus. Rauvolfia serpentina, or Indian Snakeroot, yields the alkaloids reserpine and rescinnamine, which are useful tools in the treatment of high blood pressure and even some forms of psychosis. Catharanthus roseus yields alkaloids used in treating cancer.

The genus Apocynum was used as a source of fiber by Native Americans.

The edible flower of Fernaldia pandurata (common name: loroco) is a popular part of El Salvadorian and Guatemalan cooking.

The aromatic juice of Saba comorensis (syn. Landolphia comorensis, the Bungo or Mbungo fruit is popular and highly appreciated on Pemba Island and other parts of coastal Tanzania.[8]

Gallery[edit]

References[edit]

  1. ^ a b c Endress ME, Bruyns PV (2000). "A revised classification of the Apocynaceae s.l.". The Botanical Review 66 (1): 1–56. doi:10.1007/BF02857781. 
  2. ^ Heiser CB (2003). Weeds in my garden: observations on some misunderstood plants. Portland, Oregon: Timber Press. p. 50. ISBN 0-88192-562-4. 
  3. ^ a b c Apocynaceae, Thomas Rosatti, Jepson Herbarium, [1]
  4. ^ The taxonomy and systematics of Apocynaceae: where we stand in 2012; Nazia Nazar, David J. Goyder, James J. Clarkson, Tariq Mahmood and Mark W. Chase; Botanical Journal of the Linnean Society, Volume 171, Issue 3, pages 482–490, March 2013, [2]
  5. ^ Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. 
  6. ^ 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. 
  7. ^ Rapanarivo SHJV, Leeuwenberg AJM (1999). "Taxonomic revision of Pachypodium. Series of revisions of Apocynaceac XLVIII". In Rapanarivo SHJV. Pachypodium (Apocynaceae): taxonomy, habitats and cultivation. Balkema. pp. 1–82. ISBN 978-90-5410-485-8. 
  8. ^ "Saba comorensis in Agroforestree Database". Retrieved 30 July 2012.