Asparagus officinalis L.

Asparagus

© SRTurner

Family - Liliaceae

Habit - Rhizomatous, dioecious, perennial forb.

Stems - Spreading to erect, to 2 m, herbaceous, much branched, glabrous, green. Upper branch segments linear, to 2.5 cm long, 0.5 mm broad, in groups of 1-5 per node, glabrous, sometimes appearing fascicled like pine needles.

	Main stem and leaves.
© SRTurner

	Stems.
© SRTurner

Leaves - True leaves very small, alternate, reduced to triangular scales on main stem, glabrous.

	Stems and leaves. The leaves are the tiny triangular scales visible at some nodes.
© SRTurner

Inflorescence - Single or paired flowers from nodes of aerial stems. Pedicels jointed above the middle, 8-15 m long, glabrous.

Flowers - Perianth 3-6 mm long, that of the pistillate flowers slightly shorter than that of the staminate flowers, bell-shaped, the tepals oblong-elliptic, fused at the base, rounded at apex, greenish white to greenish yellow, glabrous. Stamens 6, fused to the base of the perianth, not exserted. Filaments to 3 mm long, glabrous. Anthers orange. Style 1, with 3 short stigmas. Ovary superior, 1.8 mm long, with 3 locules, each with 2 ovules.

	Flowers.
© SRTurner

	Flowers.
© SRTurner

	Flowers.
© SRTurner

	Flower.
© DETenaglia

Fruits - Berries 8-10 mm long, globose, orange-red at maturity, glabrous, with 3-6 seeds.

	Maturing fruits.
© SRTurner

	Fruit and seeds.
© SRTurner

Flowering - May - June.

Habitat - Pastures, fencerows, fields, old homesites, disturbed sites, open woods, roadsides, railroads.

Origin - Native to Europe.

Lookalikes - None.

Other info. - This plant is found sporadically throughout most of Missouri and the continental U.S. It is easy to recognize from its large habit and frilly "leaves" which are actually highly divided stems. The flowers are small and relatively inconspicuous. Pistillate plants are more noticeable late in the season, with round red berries contrasting with the green plants.

The springtime stem shoots are the highly prized, edible stage of the plant. They are cut or snapped at ground level shortly after emerging in the early springtime, before the buds begin to open out. Aficionados stress the importance of snapping asparagus, as this practice purportedly harvests only the tender part of the shoot, leaving behind the more woody portion. A well established colony of rhizomes will continue producing shoots ("spears") for a month or more. White asparagus is obtained by simply keeping shoots covered with mulch during their development, such that chlorophyll production is arrested. White and green asparagus come from the same species or even the same plant.

Asparagus contains an unusual cyclic disulfide with the common name of "asparagusic acid." Human metabolic processing of this compound results in the well known phenomenon of smelly urine. The odor is due to a variety of volatile organic sulfur compounds and appears in the urine remarkably quickly, sometimes within 15 minutes of the vegetable's consumption. The typical half life of the odor is around 4 h. A small minority of humans do not produce smelly urine, either because the precursor is not absorbed from the gastrointestinal tract, or because it is metabolized in a different manner.

The plants growing wild in Missouri are assignable to ssp. officinalis. Most recent taxonomic classifications place this plant in the family Asparagaceae.

Photographs taken at the Martha LaFite Thompson Nature Sanctuary, Clay County, MO., 5-12-00 (DETenaglia); also at St. Joe State Park, St. Francois County, MO, 5-21-2020, and near Labadie, Franklin County, MO, 5-31-2020, 9-4-2020, and 7-9-2021 (SRTurner).