Ilex cookii
| Ilex cookii | ||||||||||||
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| Scientific name | ||||||||||||
| Ilex cookii | ||||||||||||
| Britton & P. Wilson |
Ilex cookii is a species ofthe holly genus ( Ilex ). This endemic occurs only in Puerto Rico and is "critically endangered". An English-speaking common name is Cook's Holly.
description
Vegetative characteristics
Ilex cookii grows as a shrub or small tree that reaches heights of 2 to 3, in rare cases up to 7 meters. The smooth trunk has a diameter of 13 centimeters. The light brown bark is covered with lenticels .
The leaves are divided into a petiole and a leaf blade. The petiole is 2 to 3 millimeters long. The entire, smooth and somewhat leathery leaf blade is 2.5 to 4.5 centimeters long and 1 to 1.8 centimeters wide and elliptical or oblong-elliptical with a narrowed or rounded base and a pointed or pointed upper end. The glossy top of the leaf is dark green and the underside of the leaf is light green with tiny black dots.
Generative characteristics
Ilex cookii is believed to be dioecious , similar to other holly species . However, male flowers were never discovered.
The few flowers hang on thin, 3 to 5 millimeter long flower stalks. The female flowers are radial symmetry and four or five-fold with a double flower envelope . The four or five approximately 0.5 millimeter long sepals are either rounded or blunt. The four of the five 1.5 millimeter white petals are spread apart.
The four-chamber stone fruits are spherical with a diameter of about 4 millimeters.
habitat
The habitat of Ilex cookii are elven forests at altitudes above 830 m. Elf forests are evergreen mountain forests, which are dominated by dwarf, widely branched trees with a height of up to 5 meters. Trunks, twigs and leaves are covered with bromeliads , mosses and other epiphytic plants. The causes of dwarfism are roundworms , soils with a low nutrient content, poorly developed root systems and poor groundwater extraction. The average monthly temperature is 18.3 ° C and the annual rainfall is 250 cm.
status
Ilex cookii is only known from a fully grown shrub with four root saplings from Cerro de Punta and a few young plants and seedlings widely scattered in the Toro Negro State Forest on the summit of Monte Jayuya .
The reasons for the rarity of this plant are likely to be found in the destruction of the habitat due to the construction of communication masts on Cerro de Punta. Other reasons are road construction and the trampling of vegetation.
Taxonomy
The first description of Ilex cookii in 1926 by Nathaniel Lord Britton and Percy Wilson in Botany of Porto Rico and the Virgin Islands , Volume 6, page 357. The specific epithet cookii honors the botanist Melville T. Cook , in 1926 the holotype collected.
literature
- Henri Alain Liogier: Descriptive Flora of Puerto Rico and Adjacent Islands: Spermatophyta. Editorial UPR, 1994, ISBN 0847723364 .
Web links
- Ilex cookii in the endangered Red List species the IUCN 2008. Posted by: World Conservation Monitoring Center, 1998. Retrieved on 5 August, 2008.
- (DRAFT) - Cook's Holly Taxonomy
- Photo of a herbarium specimen.