''Senna marilandica'', commonly known as Maryland senna, Maryland wild senna, and wild senna, is a

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the pea family (''

Fabaceae The Fabaceae or Leguminosae,International Code of Nomenc ...

'') native to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. It blooms in the summer with yellow flowers, followed by long seed pods, and can grow up to tall. It prefers average to wet soil.

Description

''Senna marilandica'' has green, round, unbranched stems rising from a shallow, fibrous root system, reaching a height of about . The

compound leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

are alternate and

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in ...

with four to eight pairs of opposite leaflets on each leaf. Leaflets are up to long and wide and are

ovate Ovate may refer to: *Ovate (egg-shaped) leaves, tepals, or other botanical parts *Ovate, a type of prehistoric stone hand axe *Ovates, one of three ranks of membership in the Welsh Gorsedd *Vates In modern English, the nouns vates () and ovat ...

to elliptic in shape. The

inflorescences An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

are

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

s of six to nine yellow flowers, appearing both from the leaf

axils A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

( axillary) and at the end of the stems (terminal). The axillary inflorescences are up to long, and the terminal inflorescence is about long. Each flower is about across, with five yellow

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s and five greenish yellow

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s. The

stamens The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

have prominent brownish

anthers The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

. The flowers do not have

nectaries Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...

. After the flowers are fertilized, drooping pea-like seed pods, up to long, appear.

Distribution and habitat

''S. marilandica'' is native in the United States from Nebraska to the west, Florida and Texas to the south, Wisconsin to the north, and New York to the east. It is a species of special concern in Wisconsin. The plant is found in woodland edges, open fields, and thickets, and in moist areas such as riverbanks and moist prairies.

Ecology

The flowers bloom from early July through late August, and the seed pods form from early August through late September. Bumblebees, butterflies, and solitary bees visit the flowers. Although the flowers do not have nectaries, extrafloral nectaries are located at the base of the leaves that are higher on the stem, in the inflorescence, and ants, parasitic wasps, and lady beetles feed on the nectar. Unlike many members of the pea family, ''S. marilandica'' is not nodulated by nitrogen-fixing bacteria. ''S. marilandica'' is a larval host to the cloudless sulphur (''Phoebis sennae''), orange-barred sulphur (''Phoebis philea''), sleepy orange (''Eurema nicippe''), and little sulphur (''Eurema lisa'') butterflies.

References

{{Taxonbar, from=Q7450837 marilandica Plants described in 1753 Taxa named by Carl Linnaeus Flora of the Northeastern United States Flora of the Southeastern United States Flora of the South-Central United States Flora of the North-Central United States