Hoya micrantha
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| Hook. f. |
Hoya micrantha is a plant of the genus of wax flowers ( Hoya ) of the subfamily of asclepiadoideae (Asclepiadoideae).
features
Vegetative characteristics
Hoya micrantha is an epiphytic, or lithophytic , climbing perennial plant . Adventitious roots, with which the plant anchors itself to the substrate, are formed at the internodes or only slightly below the nodes . The branching, stiff shoot axes measure 2 to 4 mm in diameter are green or reddish brown and sparsely hairy. The internodes are 3 to 8 cm, exceptionally up to 10 cm long. The leaves are divided into a petiole and a leaf blade. The fluffy hairy, stiff petioles are petiolate, usually curved and 8 to 12 mm long and 2 to 3 mm in diameter. The fleshy, very thick and convexly arched leaf blades are ovate-lanceolate or elongated-elliptical with a length of 4 to 10 cm and a width of 2 to 3.5 cm with a narrow blade base and a pointed upper end. The surface is dull green, scaly and sparsely hairy downy. The pinnate veins hardly emerge. The very small colleter (glands) at the base of the leaf blade arranged in a line. All vegetative parts of the plant contain a white milky sap . In the case of herbarium , the downy hair can be lost.
Generative characteristics
The pendulous, golden inflorescence has a flat or slightly curved flower plane and contains up to 25 flowers. The downy hairy inflorescence shafts are 5 to 10 cm, exceptionally up to 15 cm long. The rhachis inflorescence is up to 2 cm long. The flower stalks are 1 to 2.5 cm long with a diameter of about 1 mm. The stems of the outer flowers in an inflorescence are longer and strongly curved.
The hermaphrodite flowers are radially symmetrical and five-fold. The corollas have strongly bent back tips and measure 7 to 8 mm in diameter; 10 to 12 mm when the petal lobes are spread out. The flower crowns are pale pink, yellowish or reddish brown. The petal lobes are 3.8 to 5 mm long and 2.5 to 3.2 mm wide (at the base) triangular with a pointed outer end. The inside of the corolla lobes is predominantly hairy, the tips, however, glabrous. The staminal secondary crown has a height of 2 to 2.5 mm and a diameter of 4 to 5 mm and is light pink, yellow or red. The lobes of the secondary crown are 2.5 to 3 mm long and 1 to 1.4 mm wide, egg-shaped and flattened on the upper side. The inner process is erect and as high as the stamens . The outer process is split in the middle. The pollinia are elongated and upright, 400 to 500 μm long and 150 to 180 μm wide. The caudicles, which are provided with broad wings, are broad-spatulate-shaped. The elongated corpusculum (or retinaculum ) measures 140 to 170 μm in length and 50 to 80 μm in width. According to R. Rintz, the flowers remain open for up to 10 days.
Occurrence
Hoya micrantha is found in Indochina , Thailand and southern Myanmar . There it grows epiphytically or semi-epiphytically on trees or on stones in the lowlands.
Taxonomy
Hoya micrantha was first described by Joseph Dalton Hooker (bot. Abbreviation: Hook. F.) From Mergui District, Tenasserim , Myanmar. The lectotype only determined by Rodda & Juhonewe (2013) (in the herbarium of the Royal Botanic Gardens in Kew ) was collected by William Griffith. Hoya pseudovalifolia Cost. from Vietnam is, according to Rodda & Simonsson Juhonewe (2013), a synonym of Hoya micrantha Hook.f.
Hoya micrantha is assigned to the Acanthostemma section in the genus Hoya .
swell
literature
- Dale Kloppenburg, Ann Wayman: The World of Hoyas - a pictorial guide. A revised version. 248 pp., Orca Publishing Company, Central Point, Oregon, 2007 ISBN 0-9630489-4-5 (pp. 172/3)
- Michele Rodda, Nadhanielle Simonsson Juhonewe: The taxonomy of Hoya micrantha and Hoya revoluta (Apocynaceae, Asclepioideae). In: Webbia: Journal of Plant Taxonomy anf Geography , Volume 68, Issue 1, 2013, pp. 7-16. doi : 10.1080 / 00837792.2013.802937
- Surisa Somadee, Jens Kühne: Hoya 200 different wax flowers. 96 p., Formosa-Verlag, Witten 2011 ISBN 978-3-934733-08-4 (p. 64)
Individual evidence
- ^ Richard E. Rintz: The Peninsular Malaysian species of Hoya (Asclepiadaceae). Malayan Nature Journal, 30: 467-522, Kuala Lumpur 1978 (p. 472).
- ^ Joseph Dalton Hooker: The Flora of British India. Volume 4. 780 p., (Publication dates; pp. 1–256: June 1883; pp. 257–512: January 1884; pp. 513–780: August 1885) scanned at www.biodiversitylibrary.org (p. 55)
- ↑ Julien Costantin: Hoya. In: Henri Lecomte (ed.): Flore générale de l'Indo-Chine. Tome 4: Asclépiadacées à Amarantacées. Pp. 125–141, Paris, Masson, 1912 Online at Biodiversity Heritage Library , here p. 139.
Web links
- www.simones-hoyas.de - Website of Simone Merdon-Bennack ( Memento from April 11, 2005 in the Internet Archive )