Dirachma
| Dirachma | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Dirachmaceae | ||||||||||||
| Hutch. | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Dirachma | ||||||||||||
| Pigf. ex Balf.f. |
Dirachma is the only genus of the family of Dirachmaceae . Of the only two species , one is endemic to Somalia and the other to Socotra .
description
Vegetative characteristics
The Dirachma species grow as deciduous shrubs with long and short shoots.
The leaves are alternate on the short shoots. The small leaves are divided into a petiole and a leaf blade. The simple, flat leaf blade is pinnate and strongly serrate. The stomata are anomocytic or cyclocytic. The stipules are transformed into thorns.
Generative characteristics
Only one lateral flower is formed at each branch end. The four bracts form a secondary calyx. The hermaphroditic flowers are usually eight-fold with a double flower envelope (perianth). There are eight sepals and eight petals each. There is only one stamen circle; since the outer circle is absent, the fertile stamens free from one another are equally large (eight) opposite the petals with which they are not fused. The anthers are relatively large. The pollen grains have three apertures and are colporat. There is a free hypanthium (= flower cup or axis cup). The eight carpels have become a top permanent, achtkammerigen ovary overgrown. There is only one anatropic ovule per ovary chamber . The stylus ends in eight pits.
The split fruit breaks down into eight partial fruits. The seed coat (testa) is smooth.
Distribution and systematics
The two Dirachma species are endemic : Dirachma somalensis D.A.Link in central Somalia and Dirachma socotrana Schweinf. ex Balf. f. on the island of Socotra (between the Horn of Africa and the Arabian Peninsula).
The Dirachmaceae family was founded in 1959 by John Hutchinson in The Families of Flowering Plants. I. Dicotyledons , second edition, p. 248 established. It used to have the rank of a subfamily Dirachmoideae within the Geraniaceae family . The first description of the genus dirachma in 1884 by Georg August Schweinfurth in Isaac Bayley Balfour : Proceedings of the Royal Society of Edinburgh , 12, p 403 with the type species dirachma socotrana Schweinf. ex Balf. f.
swell
- The family of Dirachmaceae in APWebsite. (Section description and systematics)
- The Dirachmaceae family at DELTA. (Section description)
Individual evidence
- ↑ Dirachmaceae at Tropicos.org. Missouri Botanical Garden, St. Louis
