- Rhizomatous, dioecious, perennial.
- Spreading to erect, to 2 m, herbaceous, much branched, glabrous, green. Branches filiform, thin and drooping.
- Alternate and reduced to triangular scales on main stem, glabrous. Leaves of upper branches linear, to 2.5 cm long, 0.5 mm broad, in groups of 1-5 per node, glabrous, appearing as if in fascicles like pine needles.
- Single or paired flowers from nodes of aerial stems. Pedicels jointed, 8-15 m long, glabrous.
- 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.
- Berries 8-10 mm long, globose, red at maturity, glabrous, with 3-6 seeds.
- May - June.
- Pastures, fencerows, fields, old homesites, disturbed sites, open woods, roadsides, railroads.
- Native to Europe.
- 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 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 GI tract, or because it is metabolized in a different manner.
The plants growing wild in Missouri are assignable to ssp.
. Most recent taxonomic classifications place this plant in the family
Photographs taken at the Martha LaFite Thompson Nature Sanctuary, Clay County, MO., 5-12-00 (DETenaglia); also along the Katy Trail near Augusta, St. Charles County, MO, 4-28-2012 (SRTurner).