Dichotomanthes tristaniicarpa

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Dichotomanthes tristaniicarpa
Dichotomanthes tristaniaecarpa - Kunming Botanical Garden - DSC03211.JPG

Dichotomanthes tristaniicarpa

Systematics
Family : Rose family (Rosaceae)
Subfamily : Spiraeoideae
Tribe : Pyreae
Sub tribus : Pome fruit family (Pyrinae)
Genre : Dichotomanthes
Type : Dichotomanthes tristaniicarpa
Scientific name of the  genus
Dichotomanthes
Short
Scientific name of the  species
Dichotomanthes tristaniicarpa
Short

Dichotomanthes tristaniicarpa is the only way the plant genus Dichotomanthes and belongs to the subtribe of maloideae (Pyrinae) within the family of the rose family (Rosaceae). It occurs with three varieties only at altitudes between 1300 and 2500 meters in the Chinese provinces of Sichuan and Yunnan .

description

Branch with leaves and fruit cluster

Appearance and leaf

Dichotomanthes tristaniicarpa is a deciduous shrub or small tree that reaches heights of 2 to 7 meters. The bark of the branches is initially dense, yellowish-white, woolly hairs and gradually becomes bald, later it is bald grayish-brownish to black. The small, egg-shaped buds are woolly hairy at first and gradually bald; their upper end is blunt to more or less pointed.

The alternate leaves are divided into a petiole and a leaf blade. With a length of 4 to 6 mm, the relatively short and relatively thick leaf stalk is covered with dense yellowish-white woolly hair. With a length of 3 to 6 cm and a width of 1.5 to 2.5 cm, the simple leaf blade is usually elliptical to elongated-lanceolate, rarely obovate or obverse-lanceolate with a wedge-shaped to rounded blade base and a pointed or blunt upper end , which is usually sharply pointed. The leaf margin is usually smooth or rarely sparsely serrated above the center. Starting from the main nerve, seven to twelve lateral nerves on each side bend upwards to the leaf margin. The underside of the leaf is initially dense, yellowish-white, woolly hairs, later only thinly haired or balding. The upper side of the leaf is bare or has some hairs only along the main nerve. The early sloping side leaves are small and thready.

Inflorescence and flower

The flowering period extends from April to May. Many flowers stand together in terminal compound, umbrella- shaped inflorescences . The rachis of the inflorescence is hairy yellowish-white woolly. Most early sloping bracts are membranous and lanceolate. There are two bracts just below the sepals . The 1 to 3 mm long peduncle is hairy yellowish-white woolly.

The hermaphroditic, radial symmetry , five-fold flower has a diameter of 5 to 9 mm with a double flower envelope (perianth). The bell-shaped flower cup (hypanthium) is 2 to 3 mm in size and hairy on both sides. The five green, fleshy sepals are triangular with a serrated edge and a blunt upper end; they are shorter than the flower cup and enlarge until the fruit is ripe. The five free, white petals are nailed short and with a length of 3 to 4 mm almost circular or broadly egg-shaped with a blunt upper end or they are edged. The rarely 15 to mostly 20 stamens are shorter than the petals. The stamens are bare and smooth. There is only one upper carpel which contains only two erect ovules ; it is downy hairy in the lower area and is inserted at the base of the flower cup. The only style is glabrous and shorter than the stamens; it is almost terminal to the side of the ovary, almost terminal when the fruit is ripe. The stylus is disc-shaped and heady, lobed with an irregular edge.

Fruit and seeds

The five upright sepals are clearly visible even when the fruit is ripe. The fruits contain many seeds. The dry, hard achenes are cylindrical and glabrous with a length of 5 to 7 mm, except for the upper end, which is slightly hairy and short. The red fruit when ripe is mostly surrounded by the fleshy hypanthium. The fruits ripen in China between August and November. Each fruit contains only one flattened seed .

Chromosome number

The number of chromosomes is 2n = 34.

Systematics and occurrence

The genus Dichotomanthes was set up in 1873 with the first description of Dichotomanthes tristaniicarpa (there “tristaniaecarpa” written) by Sulpiz Kurz in Journal of Botany, British and Foreign , Volume 11 (127), p. 195. Dichotomanthes tristaniicarpa is the only species of the genus Dichotomanthes from the subtribe Pyrinae of the tribe Pyreae in the subfamily Spiraeoideae within the family Rosaceae .

The three varieties occur in forests, on the edge of the forest and on slopes only at altitudes between 1,300 and 2,500 meters in the Chinese provinces of Sichuan and Yunnan .

There are three varieties of the species Dichotomanthes tristaniicarpa :

  • Dichotomanthes tristaniicarpa var. Glabrata Rehder : The endemic species only occurs on slopes at altitudes between 1300 and 1500 meters in Simao Xian in southern Yunnan.
  • Dichotomanthes tristaniicarpa var. Inclusa L.H.Zhou & CYWu : The variety was only in 2006 and Li Hua Zhou & Cheng Yih Wu: Flora Yunnanica described from Yunnan Province, Volume 12, p 801 (303).
  • Dichotomanthes tristaniicarpa short var. Tristaniicarpa : It occurs in mixed forests, on the edges of evergreen forests and on open slopes at altitudes between 1500 and 2500 meters in the Chinese provinces of Sichuan and Yunnan.

literature

Individual evidence

  1. ↑ a b c d e Lu Lingdi (Lu Ling-ti) & Stephen A. Spongberg: Genus Dichotomanthes and Art Dichotomanthes tristaniicarpa , p. 85 - online with the same text as the printed work, In: Wu Zheng-yi, Peter H. Raven (Ed .): Flora of China, Volume 9 - Pittosporaceae through Connaraceae, Science Press and Missouri Botanical Garden Press, Beijing and Saint Louis, May 1, 2003. ISBN 1-930723-14-8
  2. ↑ a b Dichotomanthes tristaniicarpa at Tropicos.org. Missouri Botanical Garden, St. Louis
  3. ↑ First publication scanned at biodiversitylibrary.org .

Web links

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