Small-flowered clover

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Small-flowered clover
Systematics
Order : Fabales (Fabales)
Family : Legumes (Fabaceae)
Subfamily : Butterflies (Faboideae)
Genre : Clover ( trifolium )
Section : Lotoidea
Type : Small-flowered clover
Scientific name
Trifolium retusum
L.

Small-flowered clover ( Trifolium retusum ) is a species of plant from the genus Klee ( Trifolium ). It is assigned to the Lotoidea section . It is common in Europe and North Africa.

description

The small-flowered clover is an annual herbaceous plant that reaches heights of between 15 and 40 centimeters. The stem axis is bare and branches directly at the base into several stems, these are upright or ascending and are grooved. In the upper part, the stems branch out abundantly.

The alternate leaves are arranged in a petiole and a leaf blade. The lower leaves are long stalked, the upper shorter. The leaf stalks are between 0.7 and 1.5 inches long. The leaf blade triple pinnate. The individual leaflets are 0.8 and 1.8 inches long and 0.4 to 0.9 inches wide. The leaflets of the basal leaves are often oblong, obovate. The base is narrow, the leaf margin is serrated and the tip is rounded or edged. The leaf veins stand out clearly. The stipules are 0.7 to 1.5 inches long with an elongated tip.

The inflorescences measure up to 1 centimeter, the upper ones are almost sessile. The bracts are longer than the inflorescence axes and sharply pointed and folded. The flower stalks are about 1 millimeter long and bend when the fruit ripens.

The hermaphrodite flowers are zygomorphic and five-fold with a double flower envelope . The green calyx is between 4 and 5 millimeters high and ten-nerved. The awl-shaped calyx teeth are uneven and longer than the calyx tube. When the fruit ripens, all of the calyx teeth bend strongly and give the fruit a prickly appearance. The crown has the typical shape of the butterfly flower , is shorter than the calyx and whitish to pink in color. The flag is egg-shaped to narrowly tapering, slightly serrated at the tip, not edged and significantly longer than the shuttle and wing.

The legume protrudes slightly from the calyx, is egg-shaped and skin-like. The legume contains two seeds between which it is constricted. The seeds are egg-shaped and brown in color.

The number of chromosomes is 2n = 16.

ecology

The small-flowered clover is probably completely cleistogamous , which means that the flowers do not open at all during anthesis and are self-pollinating .

The diaspores , which are the fruits of the small-flowered clover, are spread via epichories , i.e. by animals. The calyx teeth on the fruit, bent like a Velcro, get caught in the fur of animals and are thus carried away.

distribution

The distribution area of ​​the small-flowered clover includes southern and central Europe, as well as the Balkan Peninsula , the Caucasus and North Africa . A smaller occurrence in Iraq has also been reported.

The small-flowered clover has its distribution center in the steppes of Southeast Europe , especially in Hungary . From there the small-flowered clover could have penetrated as far as Saxony after the ice age warm periods ; but he was probably abducted with contaminated seeds. In any case, the sporadic occurrences observed on the northern Upper Rhine or in Switzerland can only be explained in this way. In Hungary it is a species of the Festucion pseudovinae association.

It occurs sporadically in Saxony, Lower Austria and Burgenland ; otherwise it has only been introduced into Central Europe and has run wild. The populations of the small-flowered clover are not secure everywhere, but are sometimes endangered by loss of location. In Austria the species is considered critically endangered.

The small-flowered clover thrives best on lime-poor, sandy or gritty soils . It inhabits forests, clearings, steppes, pastures, gaps, dry sand lawns and roadsides.

literature

  • Michael Zohary, David Heller: The Genus Trifolium . The Israel Academy of Sciences and Humanities , Jerusalem 1984, ISBN 978-965-208-056-1 , pp. 123 .
  • John M. Gillett, Norman L. Taylor, M. Gillett: The World of Clovers . Iowa State University Press , Ames 2001, ISBN 978-0-8138-2986-9 , pp. 346 f .

Individual evidence

  1. ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp.  594 .
  2. ↑ a b c d Dietmar Aichele, Heinz-Werner Schwegler: The flowering plants of Central Europe . 2nd Edition. tape 2 : Yew family to butterfly family . Franckh-Kosmos, Stuttgart 2000, ISBN 3-440-08048-X .
  3. ↑ Harald Niklfeld: Red List of Endangered Plants Austria . 2nd Edition. Green series of the Federal Ministry for the Environment, Youth and Family, 1999, ISBN 978-3-85333-028-9 .

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