Hoya solokensis
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Hoya solokensis is a plant of the genus of wax flowers ( Hoya ) of the subfamily of asclepiadoideae (Asclepiadoideae).
features
Hoya solokensis is an epiphytic , small, non-climbing shrub. Roots are only present at the base; Adhesive roots were not observed. The shoots are upright or splayed. They have a diameter of 2.5 to 5 mm. Fresh shoots are pale green, sparsely hairy, older shoots are gray-brown and glabrous. The internodes measure 1 to 2 cm, rarely up to 5 cm. The leaves are stalked, the petioles are 5 to 10 mm long and 1 to 2 mm in diameter. They are furrowed and sparsely hairy on top. All vegetative parts secrete a white milky juice when injured. The thin, non-succulent leaf blades are elliptical, 5 to 10 cm (rarely also 12 cm) long and 2.5 to 4 cm wide. The base and apex are pointed or pointed. The bare upper side is green, the underside, which is also bare, is light green. The leaf nerve is pinnate, the central rib is slightly sunk on the upper side or is slightly protruding on the lower side. There are 4 to 7 pairs of secondary ribs. Glands on the leaf bases are absent.
The hemispherical inflorescences arise from the leaf axils and are upright or horizontal. They are unbranched and completely fall off after flowering and seed formation. They contain 3 to 10 flowers. The green inflorescence stalks are 8 to 12 mm long and 1.2 to 1.4 mm thick. They are sparsely hairy down below the rachis, otherwise glabrous. The flower stalks are 5 to 8 mm long and 1 to 1.5 mm thick, light green and sparsely hairy. The light green sepals are ovate to round with a rounded apex. They are 1.4 to 2.2 mm and at the base 1.2 to 1.6 mm wide, glabrous on the inside and hairy on the outside. The white corolla has a diameter of 1.5 cm. The corolla tube is bulbous at the base and surrounds the lower half of the secondary crown. The upper part of the tube is somewhat narrowed. The basal thickened part is 2.5 to 3 mm high and 3 to 3.5 mm in diameter. The petal lobes are narrow triangular, 5 to 6 mm long and 2.5 to 3 mm wide at the base. When opened, they are bent back with bent edges and a slightly curved tip. The corolla tube is downy hairy on the inside with backward-facing hair, outside sparsely downy hairy with splayed hair. The tips of the petals are sparsely hairy on the inside, with splayed hairs on the outside. The staminal secondary crown is 4.5 to 5 mm high and 2.5 to 3 mm in diameter. They are stiff and look waxy. The lobes are 4.5 to 5 mm long and 1 to 1.2 mm wide, and stand upright. They are elongated and curved and on the back of the dust bag attached and meet in the middle. The outer processes are blunt, with a narrow folded edge. The egg-shaped anthers measure approx. 0.5 × 0.3 mm and have a membrane-like apical appendix that covers the stylus head. The elongated pollinia are 470 to 520 mm long and 200 to 240 μm wide, with a rounded base and a rounded apex. A transparent outer edge is missing. The caudiculae are approx. 130 μm long and 70 μm thick, egg-shaped and almost transparent. The egg-shaped corpusculum measures 300 to 320 μm in length and 160 to 180 μm in width. The stylus head is pentagonal in cross section with five protrusions that alternate with the stamens. The apex is 1 to 1.2 mm high and 0.9 to 1.1 mm in diameter. The apex is pointed. Fruits and seeds were not observed.
Similar species
Hoya solokensis is similar to Hoya papaschonii Rodda (2014) from southern Thailand. Both grow shrub-like and have inflorescence stalks that are shed and a corolla tube. In Hoya papaschonii , however, the petal tips are upright. The corolla of Hoya papaschonii has staminal and interstaminal elements, while Hoya sokolensis has only interstaminal elements.
Hoya telosmoides Omlor (1996) also has a corolla tube, but is climbing. The flowers of Hoya sokolensis are similar to the Borneo species Hoya hamiltoniorum ALLamb, Gavrus, Emoi & Gokusing (2014). But this species is also climbing. In addition, the secondary crown is different, in this species the apex of the inner process is split, in Hoya sokolensis it is whole.
Geographical distribution and habitat
The species is so far only known from the type locality Solok, Sumatra, Indonesia. It grows there in the evergreen rainforest at approx. 1000 m above sea level.
Taxonomy
The taxon was established in 2019 by Sri Rahayu and Michele Rodda. The holotype has been deposited in the herbarium of the Research Center for Biology in Cibinong, Indonesia under the number Fadly sn leg. The new species was named after the locality of Solok, Sumatra.
literature
- Sri Rahayu, Michele Rodda: Hoya of Sumatra, an updated checklist, three new species, and a new subspecies. European Journal of Taxonomy 508: 1–23, 2019 ISSN 2118-9773 doi : 10.5852 / ejt.2019.508