Kadua haupuensis
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Inflorescence of Kadua haupuensis |
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| Lorence & WLWagner |
Kadua haupuensis is a plant from the genus Kadua in the family of the Rubiaceae (Rubiaceae). It is endemic to Hawaii and is thought to be potentially extinct in the wild.
description
Vegetative characteristics
Kadua haupuensis grows as a shrub that can reach heights of 1 to 1.5 meters. The brittle trunks are upright and the branches have a stem-round cross-section. The bark is hairless with the exception of the nodes. The brown bark of the older branches is longitudinally fissured.
The constantly against arranged on the branches leaves are divided into a petiole and leaf blade. The bald or hairy petiole is 0.2 to 1.6 inches long and has a narrow wing. The simple, paper-like leaf blade is elongated-lanceolate to elongated-egg-shaped with a length of 3 to 11.5 centimeters and a width of 0.7 to 3.2 centimeters. The shiny upper surface of the leaf blade is glabrous, while the underside is glabrous or sparsely hairy, with the hairiness being thicker along the central leaf vein. From each side of the central leaf vein, three to six pairs of side veins branch off and the higher-order leaf veins form a striking, net-like pattern. The bare stipules resemble the deciduous leaves, are fused with the base of the petiole and thereby form a leaf sheath covered with awn . The leaf sheath is 0.15 to 0.3 inches long and has a 0.2 to 0.5 cm long awn .
Generative characteristics
The dense panicle-like , zymous inflorescences are 2 to 4 inches long and 2 to 4.5 inches wide and are on a peduncle. The inflorescences contain 6 to 67 individual flowers.
Kadua haupuensis is dioecious ( diocesan ). The four-fold and dimorphic flowers are radial symmetry . The sepals are fused together to form a calyx tube. The bald, green and purple-tinted calyx lobes are linear-oblong to linear-inverted-lanceolate with a length of 0.25 to 0.6 centimeters and a width of 0.03 to 0.08 centimeters. The edges of the calyx lobes can be ciliated. The petals are fused together like a saucer. The obverse-cone-shaped and hairless flower cup is 0.1 to 0.15 centimeters long in the male flowers. The corolla tube reaches a length of 1 to 1.6 centimeters. The four elongated egg-shaped to elliptical corolla lobes reach lengths of 0.25 to 0.35 centimeters. The filaments are 0.2 to 0.25 centimeters long and the stylus reaches together with the scar a length of 0.4 to 1.2 centimeters. The also inverted-cone-shaped and hairless flower cup becomes 0.15 to 0.2 centimeters long in the female flowers. The corolla tube reaches a length of 0.9 to 1 centimeter. The four triangular-egg-shaped corolla lobes reach lengths of 0.2 to 0.25 centimeters. The stylus achieved together with the scar a length of 0.6 to 1.1 centimeters. Occasionally, hermaphrodite flowers also appear on the male plants. These resemble the male flowers, but have larger stamens and shorter styles.
The capsule fruits are obovate in shape with a length of 0.35 to 0.45 centimeters and a thickness of 0.4 to 0.5 centimeters wide. Each of the fruits contains numerous dark brown to almost black seeds. With a length of 0.5 to 0.6 millimeters and a width of 0.25 to 0.4 millimeters, they are irregularly obovate to elliptical in shape and the hairy seed coat has conspicuous, blister-like thickenings.
Occurrence and endangerment
The natural range of Kadua haupuensis is on the island of Kaua'i, which belongs to Hawaii . The distribution area there includes the mountain Ha'upu in the south of the island , whereby this population is considered to be extinct since a landslide.
Kadua haupuensis thrives at altitudes of around 366 meters. The species grows there on northern slopes in moderately humid forests. In these forests the koa acacia ( Acacia koa ) and Diospyros sandwicensis as well as various species of pisonia grow .
Kadua haupuensis is classified as "Critically Endangered" on the IUCN Red List and is believed to be extinct in the wild. Displacement by invasive species as well as habitat destruction by introduced and feral animals as well as landslides are named as the main threats. The total stock currently comprises 9 plants that were cultivated from seeds in the National Tropical Botanical Garden . Another 69,300 seeds are owned by the National Tropical Botanical Gardens.
Taxonomy
It was first described as Kadua haupuensis in 2010 by David H. Lorence and Warren L. Wagner in Brittonia .
Individual evidence
- ↑ a b c d e f g Kadua haupuensis. In: Flora of the Hawaiian Islands. www.botany.si.edu/pacificislandbiodiversity/hawaiianflora, accessed on January 28, 2017 (English).
- ↑ a b c Kadua haupuensis in the endangered Red List species the IUCN 2016 Posted by: DH Lorence & W. Kishida, 2015. Accessed January 28, 2017th
- ↑ Kadua haupuensis at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed January 28, 2017.
