Kadua cordata
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Kadua cordata |
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| Cham. & Schltdl. |
Kadua cordata is a plant from the genus Kadua in the family of the Rubiaceae (Rubiaceae). It is endemic to Hawaii .
description
Vegetative characteristics
Kadua cordata grows as a mostly little branched, upright to climbing dwarf shrub whose trunks can reach lengths of 0.6 to 6 meters. All shoots are glabrous and mostly conspicuously blue-green in color. The branches have a round to slightly square cross-section.
The constantly against arranged on the branches leaves are divided into a petiole and leaf blade. The petiole is 0 to 1 centimeter long. The simple, thin-skinned to thick leathery leaf blade is 3 to 16 centimeters long and 0.8 to 7.5 centimeters wide, from ovoid to broadly ovate to elliptical-ovoid and oblong-ovoid to elliptical, occasionally also lanceolate. The shiny upper side of the leaf blade is glabrous, while the blue-green underside is glabrous or finely haired, with the hairiness occasionally occurring only along the leaf veins . The base of the blade is broadly wedge-shaped, rounded, almost heart-shaped or, more rarely, tapered to a point, the tip of the blade is pointed short or long and the flat or curved back edge is entire. Several conspicuous side veins branch off from each side of the central leaf vein. The stipules resemble the deciduous leaves, are fused with the base of the petiole and thus form a spiky-tipped leaf sheath . The triangular and mostly keeled leaf sheath is 0.3 to 0.9 cm long and has a 0.1 to 0.5 cm long spike tip.
Generative characteristics
The terminal, mostly dense, rarely also open zymous inflorescences are glabrous and mostly blue-green in color. The inflorescences contain several single stalked flowers. The flower stalks are 0.2 to 1.5 centimeters long and have a square cross-section.
The four-fold flowers are radial symmetry . The top-shaped flower cup is 1.5 to 2.2 millimeters long. The sepals are fused together to form a calyx tube. The leaf-like calyx lobes are elongated-ovoid, ovoid to broad ovoid-shaped with a length of 2 to 8 millimeters and a width of 1 to 2.5 millimeters. The fleshy, mostly glaucous petals are fused together like a saucer. The corolla tube reaches a length of 0.6 to 1.7 centimeters and has an approximately square cross-section. The four pale green, greenish yellow, greenish white or cream colored and rarely purple speckled corolla lobes reach lengths of 0.15 to 1 centimeter. The stylus, which is two to four times lobed, is woolly hairy in the lower part.
The capsule fruits are gyro-shaped to approximately spherical with a length of 0.2 to 0.4 centimeters and a thickness of 0.3 to 0.7 centimeters. The endocarp is usually very lignified. Each of the fruits contains several dark brown seeds. They are irregularly wedge-shaped and their seed coat is dark, grained or scarred like a network.
Occurrence and endangerment
The natural range of Kadua cordata is on some islands belonging to Hawaii . Kadua cordata is endemic to the islands of Kauaʻi , Lānaʻi , Maui Molokaʻi and Oʻahu .
Kadua cordata thrives at altitudes of 400 to 1820 meters. The species grows there in moderately moist to moist forests and in moderately moist bushland.
Kadua cordata is classified as "Endangered" on the IUCN Red List , while the subspecies remyi is listed as "Critically Endangered". Displacement by invasive species as well as habitat destruction by introduced and feral animals as well as landslides, droughts and forest fires are named as the main endangerment factors. The total stock of the nominate form is regarded as stable while the stock of subsp. remyi is considered to be in decline and the subspecies may already be extinct.
Taxonomy
It was first described as Kadua cordata in 1841 by Adelbert von Chamisso and Diederich Franz Leonhard von Schlechtendal in Linnaea . Synonyms for Kadua cordata Cham. & Schltdl. are Hedyotis cordata (Vell.) Steud. and Hedyotis sinnendaliana Steud.
There are up to three subspecies:
- Kauda cordata subsp. cordata is the nominate form and occurs on Kauaʻi , Maui Molokaʻi and Oʻahu .
- Kauda cordata subsp. remyi (Hillebr.) WLWagner & Lorence occurs on Lānaʻi and may already be extinct.
- Kauda cordata subsp. waimeae (Wawra) WLWagner & Lorence occurs on Kauaʻi.
Individual evidence
- ↑ a b c d e f Kadua cordata. In: Flora of the Hawaiian Islands. www.botany.si.edu/pacificislandbiodiversity/hawaiianflora, accessed on January 4, 2017 (English).
- ↑ a b c Kadua cordata in the endangered Red List species the IUCN 2016 Posted by: M. Keir, 2016. Accessed January 4 2017th
- ↑ a b Kadua cordata subsp. remyi. In: Flora of the Hawaiian Islands. www.botany.si.edu/pacificislandbiodiversity/hawaiianflora, accessed on January 4, 2017 (English).
- ↑ a b Kadua cordata subsp. remyi in the endangered Red List species the IUCN 2016 Posted by: M. Keir, M. Šporkovský Koehler, SM Gon, VL Caraway, M. Bruegmann, M. Chau, J. & N. Kwon Sugii, 2016. Retrieved on 4th January 2017.
- ^ Kadua cordata at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed January 4, 2017.
- ↑ Kadua cordata subsp. cordata. In: Flora of the Hawaiian Islands. www.botany.si.edu/pacificislandbiodiversity/hawaiianflora, accessed on January 4, 2017 (English).
- ↑ Kadua cordata subsp. waimeae. In: Flora of the Hawaiian Islands. www.botany.si.edu/pacificislandbiodiversity/hawaiianflora, accessed on January 4, 2017 (English).
