Costus pulverulentus

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Costus pulverulentus
Costus pulverulentus 1.jpg

Costus pulverulentus

Systematics
Monocots
Commelinids
Order : Gingery (Zingiberales)
Family : Costaceae
Genre : Costus
Type : Costus pulverulentus
Scientific name
Costus pulverulentus
C. Presl

Costus pulverulentus is a species ofthe Costaceae family . It grows as a perennial , herbaceous plant and iswidespreadfrom eastern Mexico to northwestern South America .

description

Vegetative characteristics

Costus pulverulentus is a perennial, herbaceous plant with an underground rhizome and reaches a height of 0.2–2.5 (–3.5) m. The brightly colored, bald rhizome is 15 cm long or longer, has a diameter of 1.3–2.4 cm and has 0.3–1.6 cm long internodes . The stem -round, upright, unbranched, often spirally curved stem axis is enveloped by tubular, closed, green leaf sheaths and together with these reaches a diameter of (0.4–) 0.6–1.6 cm. The alternate leaves are arranged around the stem like a spiral staircase. The 1.2–6.1 cm long leaf sheaths have at their upper end a truncated to slightly bilobed, 3–15 (–25) mm long ligule , the edge of which is ciliate with hair-like fibers. The 2–10 (–15) ​​mm long, simple and undivided, narrowly elliptical to narrowly obovate leaf blade is (7–) 10–30 (–35) cm long and (3–) 6–12 cm wide. It has a wedge-shaped to rounded, less common heart-shaped base and has a short point at the front. The hairiness is very variable. The leaf sheaths, ligule, petioles and undersides of the blades are glabrous, short downy or shaggy hairy. The tops of the blades are bald, rarely with shaggy hairs, and tightly curly haired on the midrib. The leaf blades usually turn light brown as they dry out.

Generative characteristics

The inflorescence is a spindle-shaped, cone-like, sharply pointed spike , which is located at the end of a leafy shoot . It is 3–7 (–15) ​​cm long, has a diameter of 1.5–4.5 cm and enlarges to a length of up to 30 cm and a diameter of up to 7 cm when the fruit is ripe. The leathery, roof-tile covering, helically arranged bracts are broadly ovate-triangular, pointed to blunt and have no leaf-like appendages. Your exposed section is colored red to orange-red, occasionally also greenish, your covered section is colored red. The bracts are (2–) 2.5–3.6 (–4.5) cm long and 1.9–2.7 (–4.5) cm wide. They are hairy bald to short and woolly at the edges in short, hair-like fibers frayed to slashed, but often balding with age. Somewhat below the tip of the bracts there is a vertical, linear, 4–10 mm long thickening ( callus ) that secretes nectar . In the axilla of each bract there is a single flower . Their canoe-shaped folded, parchment-like, red to orange-red colored cover sheet is 15–23 mm long and 4–6 mm wide. It is bald to sparsely silky-haired and mostly frayed in fibers at the edge.

Costus pulverulentus , flower

The hermaphrodite , zygomorphic flowers have a perimeter that is arranged in two circles. The three reddish outer bracts ( calyx ) are fused together to form a tube. The 6–10 mm long calyx does not protrude beyond the bracts. It has three almost identical, triangular, 1–4 mm long and at its base 4–6 mm wide lobes. The calyx is bare and often has short, fibrous frayed or slashed edges. The three red, orange-red to yellow inner bracts ( crown ) are fused at the base to form a (10–) 15–20 mm long tube. The spindle-shaped, bald crown is (37–) 50–70 mm long. The three narrow verkehrteiförmigen, in the bud of each dachziegelig covering Kronzipfel are (29-) 40-50 mm long and 10-20 mm wide. The topmost tip is slightly larger than the two on the side. Five intergrown staminodes form a corolla-like, red to yellow labellum . This is 30–40 mm long, elongated, obverse-shaped when expanded and (15–) 30–40 mm wide, but with its lateral, inwardly rolled lobes, forms a slender tube approximately 8 mm in diameter. The front edge of the labellum is unequal to five lobes. All five lobes are curved back, the middle one is narrowly triangular and 4-6 mm long, the others are triangular and 2-5 mm long. The single stamen is formed like a corolla and protrudes far beyond the labellum. At the base it has grown together with the labellum to form a short, slender, papillary tube. The stamen is narrowly elliptical, 35–50 mm long, 4–10 mm wide and is pointed or blunt in front. It is the same color as the labellum in the lower part, but often has a red tip. The 4-9 mm long, consisting of two counters dust bag is adhered to the surface of the dust sheet approximately in the center thereof. The ellipsoidal, slightly asymmetrical pollen grains have a size of 104 to 138  µm . They have a smooth, 2–3 µm thick exine and are pantoporate with 5–8 pores that have a diameter of 16 to 26 µm. The bald, lower ovary is 5–10 mm long. It is threefold and contains numerous anatropic ovules in each compartment , which are attached in two rows to the central angular placenta . Towards the tip of the ovary there are two septal nectaries, i.e. nectar glands in the area of ​​the ovary septum. There is only one thread-like stylus with a scar consisting of two leaf-like, ciliate parts . This has a two-lobed appendage on the back with which it is fixed between the counters of the dust bag.

The fruits are white, ellipsoidal, about 15 mm long, ± fleshy, bald capsules , which are crowned by the remaining calyx. They are threefold and open irregularly into columns . The numerous seeds are glossy black and have a large, white, slashed aril .

Costus pulverulentus can flower and produce fruit all year round. In southern Central America ( Costa Rica , Panama ) the species mainly blooms between May and August, i.e. in the rainy season .

Chromosomes

Costus pulverulentus has a diploid set of chromosomes with 2n = 18.

distribution and habitat

Costus pulverulentus is widespread in eastern and southern Mexico and Central America . In the north, the species reaches the state of San Luis Potosí . In northwestern South America it occurs from southern Ecuador to the northwest of Venezuela , to the east to the state of Miranda . Evidence from the island of Cuba relates to cultivated occurrences.

The species occurs in the undergrowth of tightly closed tropical rainforests as well as in forest clearings and at forest edges . In Mexico it is also given for mountain forests and for forests that partially shed their leaves in the dry season . Costus pulverulentus grows regularly along watercourses and in wooded gorges . The species is also found in secondary vegetation, in ruderal locations and in plantations . The occurrences range from sea level to about 1400 (–2730) m above sea level .

Flower biology

As a rule, only one flower per inflorescence is open for a day at the same time. The long-tailed shadow hummingbird was found as the only pollinator of Costus pulverulentus at three locations in Costa Rica and Panama . The visit rate, however, was low and - depending on the population and year examined - was between 0.09 and 0.25 visits per hour and flower. This pollinator also visited Costus scaber at all three locations , which flowers at around the same time. Mutual pollination is prevented by several mechanisms, but above all by the different structure of the flowers. When Costus pulverulentus visits , the pollen is mainly deposited on the forehead of the hummingbird , more rarely on the beak . In contrast, with Costus scaber the pollen is only applied to the front part of the beak. This completely prevents the pollen from being transferred from Costus scaber to Costus pulverulentus , but only incompletely in the opposite direction. In addition, mechanisms were found that prevented fertilization even after pollination had taken place . Such incompatibilities between pollen and pistil evidently only developed between locally sympatric populations of both species.

Taxonomy and systematics

The species was described in 1827 by the Bohemian botanist Carl Presl . The basis of the first description was formed by collections that Thaddäus Haenke had made in Mexico. Costus formosus C.V. Morton , Costus laxus Petersen , Costus ruber C. Wright ex Griseb. and Costus sanguineus Donn.Sm. are synonyms .

In 1972 the Dutch botanist Paul Maas postulated a close relationship between Costus pulverulentus and Costus barbatus from Costa Rica and Costus geothyrsus from Ecuador in his work for Flora Neotropica . He also found that the latter species and the Mexican-Central American Costus pictus form hybrids and forms of introgression with Costus pulverulentus . Maas describes the species as particularly variable, especially with regard to its vegetative characteristics, such as the shape of the blades and the hairiness.

Costus pulverulentus was made by Paul Maas to the type of the Ornithophilus section, newly established by him in 1977, within the subgenus Costus . This section is therefore characterized by features that are related to pollination by hummingbirds, namely by a yellow, orange or red colored, small, tubular labellum of the flowers and equally colored bracts. A molecular biological study from 2005 on the basis of ITS and ETS sequences suggested that within the neotropical representatives of the genus Costus, pollination by hummingbirds arose several times independently of one another from forerunners pollinated by bees , especially jewel bees (Euglossini) . The two sections of Maas, Costus and Ornithophilus, have thus turned out to be non- monophyletic .

In the same study, several origins of Costus pulverulentus were contained in one clade , which also included origins of Costus scaber , Costus spicatus and Costus woodsonii , as well as a plant that was assigned with uncertainty as Costus wilsonii . They are all species that are pollinated by hummingbirds. The investigated origins of Costus pulverulentus did not form a monophyletic group within this clade. In addition, a closer relationship with the species Costus barbatus and Costus pictus also included in the study could not be confirmed.

etymology

The specific epithet pulverulentus ( lat. Dusty, dusted ) is derived from lat. Pulvis ( dust ). It refers to the collection of this plant species on which the first description is based. Their leaves are described as being dusted with white scales on the underside ( Folia ... subtus squamis albis pulverulenta ). The generic name Costus originally referred to the Indian costus root ( Saussurea costus ) and was later transferred to the current genus Costus .

swell

  • Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Birkhäuser, Basel / Boston / Berlin 1996, ISBN 3-7643-2390-6 .
  • Maas PJM 1972: Costoideae (Zingiberaceae). (Flora Neotropica Monograph 8). Hafner Publishing Company, New York, 139 pp.
  • Maas PJM, Maas-van de Kamer H. 2001: Costaceae Nakai. In: Stevens WD, Ulloa Ulloa C., Pool A., Montiel OM (eds.): Flora de Nicaragua. Vol. 1: Introducción, gimnospermas y angiospermas (Acanthaceae – Euphorbiaceae). (Monographs in Systematic Botany from the Missouri Botanical Garden 85). Missouri Botanical Garden Press, St. Louis, ISBN 0-915279-95-9 . - Costus pulverulentus - Online
  • Maas PJM, Maas-van de Kamer H. 2003: Costaceae. In: Hammel BE, Grayum MH, Herrera C., Zamora N. (Eds.): Manual de plantas de Costa Rica. Vol. II: Gimnospermas y Monocotiledóneas (Agavaceae – Musaceae). Missouri Botanical Garden Press, St. Louis, ISBN 1-930723-22-9 , pp. 413-423. - Costus pulverulentus - Online
  • Vovides AP 1994: Costaceae. In: Flora de Veracruz. Fasc. 78. Instituto de Ecología, AC, Xalapa, Veracruz, 13 pp. - PDF

Individual evidence

  1. ↑ a b c d Maas PJM 1972 , pp. 113-117.
  2. ↑ a b Kay KM, Schemske DW 2003: Pollinator assemblages and visitation rates for 11 species of Neotropical Costus (Costaceae). Biotropica 35: 198-207. - doi : 10.1111 / j.1744-7429.2003.tb00279.x
  3. ^ Goldblatt P., & Johnson DE (Ed.): Costus pulverulentus. In: Tropicos.org: Index to Plant Chromosome Numbers (IPCN). Missouri Botanical Garden, St. Louis, accessed January 21, 2013 .
  4. ^ A b Costus pulverulentus, Herbarium evidence. In: Tropicos.org. Missouri Botanical Garden, St. Louis, accessed January 21, 2013 .
  5. ↑ Vovides AP 1994 , p. 9.
  6. ↑ a b Kay KM 2006: Reproductive isolation between two closely related hummingbird-pollinated Neotropical gingers. Evolution 60: 538-552. - doi : 10.1111 / j.0014-3820.2006.tb01135.x
  7. ↑ Kay KM, Schemske DW 2008: Natural selection reinforces speciation in a radiation of Neotropical rainforest plants. Evolution 62: 2628-2642. - doi : 10.1111 / j.1558-5646.2008.00463.x
  8. ↑ a b Presl CB 1827: Costus. Linn. In: Reliquiae Haenkeanae. Tom. I, Fasc. II. Prague, pp. 111-112. - online
  9. ↑ Maas PJM 1977: Costoideae (Zingiberaceae). Additions to Flora Neotropica Monograph 8: 1-139. 1972. In: Renealmia (Zingiberaceae - Zingiberoideae), Costoideae (Additions) (Zingiberaceae). (Flora Neotropica Monograph 18). The New York Botanical Garden, New York, ISBN 0-89327-192-6 , pp. 162-213.
  10. ↑ a b Kay KM, Reeves PA, Olmstead RG, Schemske DW 2005: Rapid speciation and the evolution of hummingbird pollination in neotropical Costus subgenus Costus (Costaceae): evidence from nrDNA ITS and ETS sequences. American Journal of Botany 92: 1899-1910. - doi : 10.3732 / ajb.92.11.1899
  11. ↑ Genaust H. 1996 , pp. 518-519. - Preview in Google Book Search
  12. ↑ Genaust H. 1996 , pp. 180-181. - Preview in Google Book Search

Web links

Commons : Costus pulverulentus  - album with pictures, videos and audio files
  • Costus pulverulentus. In: Germplasm Resources Information Network (GRIN). United States Department of Agriculture (USDA), ARS, National Genetic Resources Program, National Germplasm Resources Laboratory, Beltsville, Maryland, accessed January 21, 2013 .