Mather Field Vernal Pools - Miniature Lupine

Mather Field Vernal Pools

	common name	Miniature Lupine

	scientific name	Lupinus bicolor

	family	Fabaceae (pea)

	habitat	grassland (damp)

	size	plant 4 to 16 inches tall; flower up to 5 mm

	fun facts	All Lupines have palmate (hand-shaped) leaves.

description

Member of the pea family. The plant is most noticeable for its palmate leaves and the large pea pods that hold its seeds. The blue flowers are rather tiny, especially when compared with other lupines.

Pea flowers are made up of five unusually shaped petals. The top petal is the banner petal. The two side petals are alike and are called the wing petals. The lower two petals are joined into a single boat-shaped petal called the keel petal.

life cycle

Miniature Lupine is an annual plant. It germinates following the first rains in the fall and can be ready to bloom by late March. When the seeds are mature, the pod splits violently and flings the seeds out.

ecology

Lupines are insect pollinated. The insect lands on the wing petals. These sway under the insect's weight and cause the stamens and/or stigma to brush up against the insect's under side.

Lupines only make a small amount of nectar for the pollinator. To advertise that the flower is un-pollinated and has nectar, the banner petal is bright white. After the flower is pollinated, the banner petal turns reddish-purple and no longer advertises the flower to insects.

The genus name Lupinus means wolf. Plants of this genus were once thought to rob the soil of nutrients because they tend to grow in poor soils. We now know that Lupines can occur on the poorest of soils because they collect atmospheric nitrogen and actually make the soil richer in nutrients.