Grevea madagascariensis
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Grevea madagascariensis |
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| Grevea madagascariensis | ||||||||||||
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Grevea madagascariensis is a plant type from the genus Grevea . The species occurs in Madagascar .
description
Vegetative characteristics
Grevea madagascariensis are mostly 2 to 3 m high shrubs or trees . Old trunks are pale brownish or grayish white and have fine longitudinal cracks and densely distributed cork pores . Clear leaf scars are present on the lower nodes . The younger branches are green and have white cork pores. Young buds are covered with indistinct, short to clearly visible woolly hairs.
The leaves are opposite. Their leaf blades are hairless, elliptical to ovate-elliptical or almost round, 4 to 19 cm (occasionally up to 25 cm) long and 1.6 to 8.5 (occasionally up to 20 cm) wide. Towards the front they are narrowly pointed or rarely also rounded, the base is wedge-shaped to rounded or, with larger leaves, rarely also clearly heart-shaped. Four or five pairs of curved lateral nerves extend from the main artery. The petiole is 0.7 to 4 cm long.
Inflorescences and flowers
The male inflorescences are cymes of six to twelve flowers , the inflorescence stalk is 1.2 to 3.8 cm long, the flower stalks 3 to 9 mm. The calyx of the male flowers is 1 to 2 mm long. The petals are oblong to oblong-spatulate and 3 to 4.2 mm long and 2 to 3 mm wide. They are rounded and slightly narrowed at the base, often they are slightly irregularly jagged. The stamens consist of 1.2 to 3 mm long stamens and 2 to 2.2 mm long anthers . The ovary is completely absent or is only rudimentary with a length of 0.5 mm.
The female flowers have a calyx with a 1.2 cm long calyx tube, which is slightly expanded at the base and is cylindrical at the top. It is either smooth or covered with indistinct nodules arranged in longitudinal stripes. The flower stalk is 3 to 7 mm (rarely up to 9 mm) long. The calyx lobes are broadly triangular and about 0.5 to 1 mm long. The petals are elongated spatulate and 4.8 mm long and 2.2 mm wide and bent back, as well as slightly jagged irregular. The tip is rounded, the base slightly narrowed. The stamens, which have regressed to staminodes , consist of 2 mm long stamens and 1.2 mm long, triangular anthers. The stylus is 4 to 5 mm long, the scars are 1.5 to 1.8 mm long.
Fruits and seeds
The fruits are bottle-shaped, 3.2 to 4 cm long and 1 to 1.2 cm wide. They are either brownish, indistinctly ribbed and weakly reticulated, or they are grayish with clearly nodular ribs. At the top is the permanent stylus. Most of the 4 to 16 (rarely up to 18 or, according to other sources, up to 24) seeds are reddish brown, elliptical, almost spherical, 5.5 mm long and 4.5 mm thick and slightly indented. The surface is finely reticulated.
Systematics and occurrence
The species occurs in Madagascar . Two subspecies are distinguished within the species:
- Grevea madagascariensis ssp. madagascariensis with smoother fruits
- Grevea madagascariensis ssp. leandrii Bosser with fruits with more pronounced groups.
A variant from Kenya incorrectly described as a subspecies keniensis is now listed as a variety of the species Grevea eggelingii .
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Individual evidence
Most of the information in this article has been taken from the sources given under literature; the following sources are also cited:
- ^ A b Bernard Verdcourt: A Reappraisal of the Grevea (Montiniaceae) Growing on the Kenya Coast. In: Kew Bulletin. Vol. 51, No. 4, 1996, ISSN 0075-5974 , pp. 771-773, JSTOR 4119730 .
literature
- George E. Schatz: Generic Tree Flora of Madagascar. Royal Botanic Gardens et al., Kew 2001, ISBN 1-900347-82-2 .
- Bernard Verdcourt: Montiniaceae (= Flora of Tropical East Africa. ). Royal Botanic Gardens et al., Kew et al. 1973, ISBN 0-85592-026-2 .
