Hoya burmanica
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Hoya burmanica is a plant of the genus of wax flowers ( Hoya ) of the subfamily of asclepiadoideae (Asclepiadoideae). The species is native to Myanmar and Assam (India).
features
Hoya burmanica is an epiphytic sparsely branched shrub. The shoots initially grow upright, later they hang. They are 40 cm long, in culture up to 2 m. They are round in cross-section and measure 3 to 5 mm in diameter. They are hairy, older shoots lignified and often become bald. The internodes are (1–) 5 to 10 (–15) cm long. The opposite leaves are petiolate. The stems, which are round in cross-section and 2.5 mm thick, are 3 to 5 cm (-10) cm long and studded with bristles. The leaf blades are triangular to ovate-lanceolate, 3 to 10 cm and 1 to 3 cm wide. They are fleshy-leathery with a pointed apex and an obtuse-angled base. The edges are bent over. The upper side is dark green to yellowish with gray spots when the leaves are exposed to full sun. The underside is light green. The top and bottom are sparsely hairy, but become bald with age. The leaf veins are barely visible, only the midrib is slightly raised and dark green on the underside. The secondary ribs can hardly be seen.
The umbel-shaped inflorescences arise individually from the nodes and contain up to 12 flowers. The top is convex. The finely hairy peduncle is persistent, 3 to 7 cm (rarely up to 10 cm) long and measures 1.5 to 2.5 mm in diameter. The rounded stigmas of earlier inflorescences remain visible at the base. The sparsely hairy flower stalks are 10 to 20 mm long with a diameter of about 1 mm. The light green flower buds are flattened apically (above). The light green to yellow corolla measures 10 to 14 mm in diameter. The sepals are triangular with a pointed or round apex. They are 1.5 to 2 mm long and about 1 mm wide. On the outside they are bristly hairy with 1 or 2 multicellular glands (Colleter) at the base. The corolla lobes are triangular to broadly ovate and pointed to slightly lobed ending. They are spread horizontally directly on the flower stalk and then bend upwards at a 45 ° angle. The lobes are about 6 mm long and 4 mm wide at the base. They are bald at the base and finely haired towards the tip, the tip itself is again bald. The stem of the secondary crown has a ring of long bristles. The secondary crown is dull yellow with a pink colored center. It is approx. 3 mm high and measures 4 to 5 mm in diameter. The tips of the secondary crown are boat-shaped, 2 to 2.5 mm long and 1 to 1.5 mm wide. The outer process is round, apically flattened with basally bent edges. The inner process is pointed. The flowers stay open for about 7 days. They only smell faint.
The pollinarium measures 825 × 550 μm. The Pollinia are elongated, apically truncated at an angle. They measure 550 μm in length and have a maximum width of 250 μm. The corpusculum has two lateral, membranous wings. The central part measures 330 μm in length and 125 μm in width, or 450 μm with the wings. The caudiculum (translator arm) is 150 μm long. The follicle stands individually on the stem. It is 5 cm long with a diameter of 1 cm.
Similar Art
Hoya burmanica is very similar to Hoya pandurata Tsiang (1939). It differs, however, by the more strongly recurved petal tips and by the significantly shorter pollinia or significantly smaller length / width ratio.
Geographical distribution and habitat
The distribution area extends from Thailand over the central parts of Myanmar to Assam (India) and Bangladesh . Aveyranov et al. also found the species in Vietnam.
The habitat of a specimen collected in 2007 was a seasonally dry rainforest with low trees 800 to 1000 m above sea level. According to Aveyranov et al. Hoya burmanica also grows lithophytically in Vietnam on steep limestone cliffs at an altitude of 1350 to 1500 m above sea level.
Taxonomy
The taxon was established by Robert Allen Rolfe in 1920. The type was a plant in culture at Kew Gardens. Rodda & Simonsson Juhonewe designated specimen K000449127 as the lectotype.
literature
- Surisa Somadee and Jens Kühne: Hoya 200 different wax flowers. 96 p., Formosa-Verlag, Witten 2011 ISBN 978-3-934733-08-4 (p. 33)
- Michele Rodda, Nadhanielle Simonsson Juhonewe: Taxonomic notes on the long-lost Hoya burmanica (Apocynaceae, Asclepiadoideae) from Myanmar. Kew Bulletin, 67: 565-570, 2012
Individual evidence
- ↑ Leonid Vladimirovich Averyanov, Van The Pham, Tatiana V. Maisak, Tuan Anh Le, Van Canh Nguyen, Hoang Tuan Nguyen, Phi Tam Nguyen, Khang Sinh Nguyen, Vu Khoi Nguyen, Tien Hiep Nguyen, Michele Rodda: Preliminary checklist of Hoya ( Asclepiadaceae) in the flora of Cambodia, Laos and Vietnam. Turczaninowia, 20 (3): 103–147, 2017 doi : 10.14258 / turczaninowia.20.3.10 , here p. 110.
- ^ Robert Allen Rolfe: Hoya burmanica Rolfe (Asclepiadeae – Marsdenieae) in Decades Kewenses C – CI. Bulletin of Miscellaneous Information (Royal Botanic Gardens, Kew), 1920: 335–344, 1920 online at www.biodiversitylibrary.org (p. 343)