Lotus corniculatus (Bird’s foot trefoil)

Lotus corniculatus L.

Bird’s foot trefoil

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Rosidae	Roses, legumes, proteas, dogwoods, hydrangeas, mistletoes, euphorbias, grapes, many more
Order	Fabales	Legumes (pea and bean families)
Family	Fabaceae	Legume family (peas and beans)
Genus	Lotus	Includes trefoils and deervetches, but not (ironically) lotus flowers (Lotus, from Greek, meant a fruit that made people forget their homes)
Species	corniculatus	Means “horned”

About plant names...

Bird’s foot trefoil is native to the temperate grassland regions of North Africa and Eurasia. They are naturalized in North America, now widespread, and invasive in some areas. The name stems from the fruits, which resemble a bird’s foot.

Identification: Plants are 6-24" (15-60 cm) tall. Leaves, pointed ovals in shape, occur in groups of five per petiole. A group of three at the end emerge from the same point, and are ½" (1.3 cm) × ⅛" (3.2 mm). The remaining two are lower, smaller, and opposite to each other. Attractive, bright yellow flowers appear in clusters of two to eight. Flowers become more orange in color over time. Each flower is bilaterally symmetrical, composed of 3 upper and 2 lower lobes, about ½" (1.3 cm) around. Thin red lines are visible on the upper lobe at close quarters. The fruits are shaped like beans, about 1" (2.5 cm) × ⅛" (3.2 mm), in small groups. The fruits’ long straight shape and emergence from a central point resemble a bird’s foot. Fruits are green, maturing to dark red. Like other members of the pea family, these plants trap atmospheric nitrogen, making their own fertilizer, allowing them to colonize soils that other plants cannot.

In ultraviolet light, bird’s foot trefoil beckons bees (who, unlike us, can see ultraviolet) very differently—bright red, with blue edges! The photo is by Bjørn Rørslett, who has photographed many flowers in UV light.

Online References:

Lotus corniculatus on Missouriplants.com

Lotus corniculatus on Invasive.org, Center for Invasive Species and Ecosystem Health

Lotus corniculatus on the Connecticut Botanical Society's Connecticut wildflowers site

Lotus corniculatus at the University of Wisconsin's Robert W. Freckmann Herbarium

Lotus corniculatus on Plants for a Future, a resource and information centre for edible and otherwise useful plants

Lotus corniculatus on CalPhotos

Lotus corniculatus on Wikimedia Commons

Lotus corniculatus on eFloras

6/5/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 2½ × 2" (6 × 5.3 cm)

8/7/2013 · Amos Kendall Conservation Land, Dunstable, Massachusetts
≈ 9 × 6" (22 × 15 cm)

8/26/2007 · Oregon
≈ 9 × 6" (23 × 15 cm) ID is uncertain

9/3/2020 · Mitchell Field, Harpswell, Maine
≈ 4½ × 3" (11 × 7.5 cm)

6/27/2012 · Townsend Wildlife Management Area, Townsend, Massachusetts
≈ 4 × 3½" (11 × 9.2 cm)

6/5/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 1 × ⅞" (2.7 × 2.5 cm)

6/27/2016 · Nashua River Rail Trail, near Na, Ayer, Massachusetts

8/27/2016 · Williams Barn and Sørhaug Woods, Groton, Massachusetts

9/3/2020 · Mitchell Field, Harpswell, Maine
≈ 4½ × 7" (12 × 18 cm)

Lotus corniculatus description by Thomas H. Kent, last updated 7 Sep 2020.

6/27/2012 · Townsend Wildlife Management Area, Townsend, Massachusetts
≈ 4 × 3" (9.9 × 7.9 cm)

8/4/2006 · Mt. Mansfield, Stowe, Vermont ID is uncertain

8/25/2007 · Oswald West State Park, Oregon
≈ 4 × 2½' (1.2 × 0.8 m) ID is uncertain

8/27/2016 · Williams Barn and Sørhaug Woods, Groton, Massachusetts

Flowers redden as they age. · 6/27/2016 · Nashua River Rail Trail, near Na, Ayer, Massachusetts

9/3/2020 · Mitchell Field, Harpswell, Maine
≈ 7 × 4" (16 × 11 cm)

The closed buds are red. · 6/8/2012 · Townsend Wildlife Management Area, Townsend, Massachusetts
≈ 3½ × 5" (9.6 × 13 cm)

6/8/2012 · Townsend Wildlife Management Area, Townsend, Massachusetts
≈ 4½ × 3" (11 × 7.9 cm)

6/19/2021 · Long Reach Preserve, Harpswell, Maine
≈ 5 × 4" (13 × 10 cm)

6/5/2010 · Nashua River Rail Trail, Groton Center, Groton, Massachusetts
≈ 5 × 4½" (13 × 11 cm)

8/27/2016 · Williams Barn and Sørhaug Woods, Groton, Massachusetts

5/30/2015 · Townsend Wildlife Area
≈ 5 × 8" (13 × 19 cm)

6/27/2016 · Nashua River Rail Trail, near Na, Ayer, Massachusetts

Range:

About this map...