Hoya revoluta

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Hoya revoluta
Systematics
Order : Enzianartige (Gentianales)
Family : Dog poison family (Apocynaceae)
Subfamily : Silk plants (Asclepiadoideae)
Tribe : Marsdenieae
Genre : Wax flowers ( hoya )
Type : Hoya revoluta
Scientific name
Hoya revoluta
Wight ex Hook.f.

Hoya revoluta is a plant of the genus of wax flowers ( Hoya ) of the subfamily of asclepiadoideae (Asclepiadoideae).

features

Vegetative characteristics

Hoya revoluta is a perennial plant and grows as a writhing, climbing epiphyte . The stem -round, bald, strong, green to reddish-brown shoot axes measure 2 to 4 millimeters in diameter. The internodes are usually 2 to 6 cm long, rarely longer. At the internodes or just below the nodes , adventitious roots are formed, with which the plant anchors itself to the substrate.

The tufted leaves are divided into a petiole and a leaf blade. The round, usually curved, dark green to reddish brown leaf stalks flatten slightly towards the base of the leaf blade . The leaf stalks are up to 3 to 8 millimeters long and measure 2 to 3 millimeters in diameter. The comparatively very thick, fleshy and bare leaf blades are elliptical, ovate to ovate-lanceolate, 2 to 5 cm long (rarely up to 9 cm), and 1 to 2.5 cm wide. The base of the blade is pointed long, the upper end of the blade is also pointed long. The somewhat thickened leaf margins are strongly bent back. The pinnate veins are only indistinctly pronounced. The small, basal colleters (small glands) sit on the top of the midrib near the transition to the stalk between the thickened leaf margins.

Generative characteristics

The inflorescences can have up to 25 (30) single flowers. They hang on a rigid, up to 5 cm long inflorescence stem. The level of the individual flowers is slightly sunk in the middle. Therefore, the stalks of the outer flowers of the inflorescence are significantly longer than the stalks of the flowers, which are arranged more in the middle. The length of the flower stem varies from 0.2 to 5 cm, the outer stems are therefore also strongly curved, the central ones rather straight. They have a diameter of 0.6 millimeters. The hermaphroditic flowers are radial symmetry . The very small, elongated sepals are blunt. The pale pink corolla with a bell-shaped corolla tube (1.6 to 1.8 millimeters in diameter) has a (total) diameter of around 4 to 5 millimeters when the petal tips are bent, or 7 to 10 millimeters when they are spread out. The triangular, slightly keeled petal lobes are 2.5 to 3.5 millimeters long and 2 to 2.7 millimeters wide at the base. Usually they are strongly bent back. The edges are bent outwards. On the inside, they are mostly lightly downy hairy, the tips are bald. The secondary crown is 1.5 to 2 millimeters high, and measures 2.7 to 3.7 millimeters in diameter. The tips of the secondary staminal crown are elliptical in shape, flattened on the upper side, 1.8 to 2.2 millimeters long and 1 to 1.2 millimeters wide. The outer, white or pale pink process is deeply split in the middle. The deep red, whitish or pale pink inner process is long, pointed and ascending, and about as long as the stamens. The elongated stamens are upright and membranous. The base is rounded, the outer end cut off bluntly. The stylus head is conical-pointed. The pollinia are elongated, blunt and winged, 210–250 μm long and 100–110 μm wide. The caudiculae are short, thick and spatulate. The corpusculum (also called retinaculum) is comparatively small, narrow-ovoid, about 80–110 µm high and 35–50 µm wide. The spindle-shaped fruits are up to 25 cm long, with a diameter of only 2 millimeters.

Chromosome number

The number of chromosomes is 2n = 22.

Geographical distribution and habitat

Hoya revoluta occurs in Indonesia ( Sumatra , Jemaja and Kalimantan ), Malay Peninsula and Singapore . It grows in sunny locations, even in full sun, in lowland rainforests.

Taxonomy

Hoya revoluta was first described in Malaysia by Joseph Dalton Hooker (bot. Abbreviation: Hook.f.). Forster & Liddle (1992) erroneously determined a herbarium specimen that has neither an exact location nor a date of collection for the lectotype . In addition, this "specimen" only consists of a few flowers in an envelope. Rodda & Juhomnewe (2013) therefore identified a herbal specimen with leaves and flowers from the Henderson collection in the Singapore Botanical Gardens as the epitypus . Hoya ovalifolia Wallich (see above) is an invalid name (nom. Inval.) According to Art. 32.1c, but probably belongs to this species.

supporting documents

literature

  • Christiane Hoffmann, Ruurd van Donkelaar & Focke Albers: Hoya. In: Focke Albers, Ulli Meve (Hrsg.): Succulents Lexicon Volume 3 Asclepiadaceae (silk plants) . Pp. 147-160, Ulmer, Stuttgart 2002, ISBN 3-8001-3982-0 (p. 158).
  • Richard E. Rintz: The Peninsular Malaysian species of Hoya (Asclepiadaceae). Malayan Nature Journal, 30: 467-522, Kuala Lumpur 1978.
  • Michele Rodda, Nadhanielle Simonsson Juhonewe: The taxonomy of Hoya micrantha and Hoya revoluta (Apocynaceae, Asclepioideae). Webbia: Journal of Plant Taxonomy anf Geography, 68 (1): 7-16, 2013 doi : 10.1080 / 00837792.2013.802937
  • Paul Irwin Forster, David J. Liddle: Taxonomic studies on the genus Hoya R.Br. (Asclepiadaceae) in Papausia. 4. Typification and synonymy of Hoya revoluta Wight ex JD Hook. Austrobaylea, 3: 638-639, 1992.

Individual evidence

  1. ↑ Hoya revoluta at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
  2. ^ Joseph Dale Hooker: The Flora of British India. Vol. 4. 780 p., (Publication dates; pp. 1–256: June 1883; pp. 257–512: January 1884; pp. 513–780: August 1885) online at www.biodiversitylibrary.org (p. 55)

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