Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Tribe: Loteae
Genus: Lotus
Species: L. pedunculatus
Binomial name: Lotus pedunculatus
Synonyms: Lotus uliginosus
Common names: Greater birds-foot-trefoil, Big trefoil, Marsh bird's-foot trefoil, Lotus major

Lotus pedunculatus is a perennial herbaceous plant and a member of the pea family (Fabaceae). It is native to Europe. It is common in the higher rainfall areas throughout New Zealand and is not of major concern, as it is mainly a garden weed and a pasture species. It can be a weed of wetlands. 
The positive side of L. pedunculatus is that it has underground rhizomes which can store carbohydrate in autumn for overwintering, making the plant useful in South Island high country. It contains condensed tannins which improve protein absorption by grazing animals.

Lotus pedunculatus it is scrambling herb, either forming dense yellow flowered patches or scrambling through other vegetation, growing 20–80 cm tall, with leaflets 10–25 mm long and 10–20 mm broad.
The hollow stems are not able to support their own weight, at first ascending, then if not grazed they sprawl loosely on the ground in an interwoven mat.
The leaves are pinnate with 5 leaflets, up to 3 cm long, and they are almost hairless to quite obviously hairy.
L. pedunculatus small flowers are a bright yellow (c. 1 cm) and are borne in clusters of 5-15 as an umbel at the tip of an upright stem.
The seed its pods are straight, rounded, pointed and are attached to a central point like spokes of a wheel. The small seeds are about 1 mm across.

Lotus pedunculatus growing roadside South Taranaki
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1-Lotus pedunculatus Lotus .JPG

A developing flowerhead. Flowerheads can have a cluster of more than 12 flowers.
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1-Lotus pedunculatus Lotus -001.JPG

1-Lotus pedunculatus-001.JPG

A growing tip with hairs traping water droplets
1-Lotus pedunculatus Lotus -003.JPG

1-Lotus pedunculatus Lotus -002.JPG 

Developing seed head.
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Developing seedhead.
1-Greater Bird s-foot-trefoil Lotus pedunculatus-007.JPG

Seed heads
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1-Lotus pedunculatus, Christiaan Sepp.jpg  
Thanks to Wikipedia for text and Information: http://creativecommons.org/licenses/by-sa/3.0/