Akaniaceae
| Akaniaceae | ||||||||||||
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Akania bidwillii |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Akaniaceae | ||||||||||||
| Stapf |
The Akaniaceae are a small family of plants in the order of the cruciferous (Brassicales) with two monotypical genera .
description
Vegetative characteristics
The two species of the Akaniaceae family grow as deciduous ( Bretschneidera ) or evergreen trees . The young shoot axes have separate vascular bundles . The change-constant leaves are pinnate with toothed or ganzrandigen pinna leaflet .
Generative characteristics
The slightly zygomorphic or radial symmetry flowers are five-fold with a double flower envelope . The five sepals are more or less fused. The five petals are twisted or not. The Androeceum consists Akania of one or two circuits, each with four or five stamens fertile or Bretschneidera eight fertile stamens . The pollen is colpat. Per carpel there are two apical , hanging (in Bretschneidera campylotrope) ovules with bistomal micropyle . The scar is small and three-lobed.
The loculicidal capsule fruits open when ripe. The seed coat (testa) is thick with thick-walled cells. The endosperm can be present. The cotyledons ( cotyledons ) are great.
The basic chromosome number is x = 9, both genera are dipoid with 2n = 18.
distribution
Bretschneidera sinensis is native to southeast China , bordering Vietnam and Taiwan, and Akania bidwillii is native to the rainforests of Australia .
Systematics
The Akaniaceae family was established in 1912 by Otto Stapf in Bulletin of Miscellaneous Information Kew , p. 380. The Akaniaceae family, together with the Tropaeolaceae family, form the basal group within the order Brassicales .
The Akaniaceae s. l. consists of two monotypical genera:
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Akania
Hook. f. : With the only kind:
- Akania bidwillii (Hend. Ex Hogg) Mabb. (Syn .: Akania hillii Hook. F. , Akania lucens Airy Shaw ): With radially symmetrical flowers and endosperm , but possibly without myrosin cells. It occurs from southeast Queensland to northeast New South Wales.
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Bretschneidera Hemsl. : With the only kind:
- Bretschneidera sinensis Hemsl. (Syn .: Bretschneidera yunshanensis Chun & FC How ): With slightly zygomorphic flowers. It occurs from the eastern Himalayas to southern China, Taiwan, Thailand and Vietnam.
It was disputed whether the two species should be run as one family or separately as two families, according to this point of view, Bretschneidera sinensis alone forms the family Bretschneideraceae Engler & Gilg , and Akania bidwillii alone forms the Akaniaceae Stapf s. st.
Tribal history
Fossil records of representatives of the Akaniaceae go back to the Palaeogene and so far all come from Patagonia in South America . The oldest finds in the form of leaf remains belong to the Salamanca Formation and are around 64 million years old, which corresponds to the Paleocene . Somewhat more recent finds were found in the Ventana Formation , which dates to the Lower Eocene between 52 and 47 million years ago; here, too, are leaves. Finds of fossilized wood from the Santa Cruz Formation of the Lower Miocene 16 to 18 million years ago are also significant . The fossil records from South America expand the known range of the family considerably. They also confirm the biogeographical links between South America, Australia and Antarctica during the Paleogene.
swell
- The akaniaceae family in APWebsite. (Section description and systematics)
- Akaniaceae s. st. with the only genus Akania in Bretschneideraceae with the only genus Bretschneidera in Delta by L. Watson & MJ Dallwitz. (Section description and systematics)
Individual evidence
- ↑ a b c Entry in Tropicos .
- ↑ a b c Rafaël Govaerts (ed.): Akaniaceae. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved October 5, 2018.
- ↑ Mariana Brea, Alejandro F. Zucol, M. Susana Bargo, Juan Carlos Fernicola and Sergio F. Vizcaíno: First Miocene record of Akaniaceae in Patagonia (Argentina): a fossil wood from the early Miocene Santa Cruz formation and its palaeobiogeographical implications. Botanical Journal of the Linnean Society 183, 2017, pp. 334-347
