Hoya rundumensis
| Hoya rundumensis | ||||||||||||
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| Hoya rundumensis | ||||||||||||
| ( T. Green ) Rodda & Simonsson |
Hoya rundumensis is a plant of the genus of wax flowers ( Hoya ) of the subfamily of asclepiadoideae (Asclepiadoideae). So far it is only known from the Malaysian part of the island of Borneo .
description
Vegetative characteristics
Hoya rundumensis is an epiphytic growing vine . It is attached to the subsurface with adhesive roots on the internodes directly below the nodes . The stem axis has a diameter of 3 to 5 millimeters and is only partially hairy when young. The internodes are 10 to 20 centimeters long, in exceptional cases only 5 centimeters long.
The leaves are divided into a petiole and a leaf blade. The downy hairy petioles are round, 15 to 20 mm long with a diameter of approx. 3 mm. The stiff, fleshy, strongly succulent leaf blades are egg-shaped to elliptical with a length of rarely 5 to, mostly 8 to 15 centimeters and a width of rarely 3 to, usually 4 to 6 centimeters. The matt green surface is flaky and bare. The pinnate veins are not visible in the fresh specimen, the midrib is very faintly visible in the dried material. The leaf base is pointed and the upper end pointed (akuminate). One or two roundish (sap) glands are located at the base of the blades.
Generative characteristics
The flat or only slightly arched, umbel-shaped inflorescences are multi-flowered with up to 30 flowers. The perennial inflorescence shafts are bent downwards (positive geotropic) and have a length of 10 to 15 centimeters and a diameter of about 3 millimeters. The flower stalks are 1 to 3.5 inches long with a diameter of about 1 millimeter. The length increases from the center of the inflorescence outwards, the outer flower stalks are also curved inwards.
The hermaphrodite flowers are five-fold and zygomorphic with a double flower envelope . The corolla is turned back and has a diameter of 7 to 8 millimeters or 10 to 12 millimeters when the petal tips are spread out. The petals are fused about halfway ( sympetalie ). The triangular, outwardly curved petal lobes with a pointed upper end are dark pink-red. They are hairy on the inside, the tips are bald. The staminal secondary crown is 2 to 2.5 millimeters high and has a diameter of 4 to 5 millimeters. It is dark red with a white spot in the center. The tips of the secondary crown are egg-shaped and flattened on the upper side; 2 to 2.5 millimeters long and 1 to 1.4 millimeters wide. The inner process is erect and is as high as the stamen . The outer process is slit in the middle (bilobat). The elongated, upright pollinia are about 400 μm long. The "caudiculae" are broadly spatulate and broadly winged. The “retinaculum” is 150 μm long and 90 μm wide.
Geographical distribution and habitat
Hoya rundumensis has so far been found in Sabah and Sarawak ( Malaysia ). There it grows epiphytically on trees in the lower zone of tropical mountain forests at altitudes of about 1000 meters.
Taxonomy
It was first described in 2010 by Ted Green (bot. Abbreviation: T. Green ) as Hoya plicata subsp. rundumensis in Asklepios , vol 108, p 19. The collected at round (Sabah, Malaysia) cuttings was Ted Green in his garden in Kaaawa , Oahu , Hawaii, cultured and allowed to flower. The holotype ( Green 2010.001 ) is kept in the herbarium of the Bernice P. Bishop Museum in Honolulu , Oahu, Hawaii .
Michele Rodda and Nadhanielle Simonsson Juhonewe upgraded the subspecies to a species, because the taxon shows significant differences to Hoya plicata and Hoya micrantha . In contrast to the two species mentioned, the leaves of Hoya rundumensis are strongly succulent and hard-leaved. The surface is flaky and rough. There is a slight depression at the base of the leaf / transition to the petiole. In Hoya plicata there is a similar slight depression, but it is absent in Hoya micrantha . Hoya rundumensis has fluffy hairy petioles (as in Hoya micrantha ), while the petioles of Hoya plicata are glabrous.
supporting documents
literature
- Richard E. Rintz: The Peninsular Malaysian species of Hoya (Asclepiadaceae). In: Malayan Nature Journal , Volume 30, Kuala Lumpur 1978, pp. 467-522.
- 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, No. 1, London 2013, pp. 7-16. doi : 10.1080 / 00837792.2013.802937
Individual evidence
- ↑ Ted Green: A new subspecies of Hoya from Rundum, Sabah, Malaysia. In: Asklepios , Volume 108, 2010, pp. 19-21.