Leucoagaricus leucothites, also found in older mycological literature as Leucoagaricus naucinus or Lepiota naucina and commonly known as the white dapperling or the Smooth Parasol, is a medium to large, smooth, white lawn mushrooms on a graceful, ringed stalk.
This species was first described as Agaricus leucothites in 1835 by the Italian physician and mycologist Carlo Vittadini. However, in 1977 the Ukrainian Solomon P. Wasser created the genus of Leucoagaricus and placed this species within it under the name of its currently accepted binomial name, Leucoagaricus leucothites.
The etymology of this specie’s name is also quite interesting. The genus name “Leucoagaricus” refers to the fact that this species is a white-capped (“Leukos”) mushroom with gills (“agaricus”). As for the epithet Leucothites, this refers again to the white coloration of the mushroom (“Leuco”) and the comparatively less desirable quality of this species (“Thitikos” – the lowest class of Greek Society). [i]
The various synonyms reads may encounter this species as Agaricus leucothites; Agaricus holosericeus; Agaricus naucinus; Lepiota naucina; Lepiota holosericea; Annularia laevis; Lepiota naucina var. leucothites; Leucocoprinus holosericeus; Leucoagaricus naucinus; Lepiota leucothites; Leucoagaricus holosericeus.
Leucoagaricus leucothites is a common cosmopolitan mushroom with a white to grayish cap, membranous annulus/ring, free gills, white spores, and fondness for grassy places and disturbed grounds.
Cap: The cap of this species measures 5-15 cm in diameter. Its shape varies with age. While young the cap has a round, convex appearance resembling an egg or a motorcycle helmet. However, as the mushroom ages, the cap expands to a broadly convex or nearly flat shape with a low, broad, rounded hump. The color of the cap is dull white when young, but with age it changes to a pale cream-ochre color with a slight grey or pinkish central hump. The cap surface is dry, smooth, and silky. With age, or with dry weather, the surface of the cap may become fibrous and covered with numerous small flakes or may break up into scales.
Flesh: The flesh of the cap is white, thick, and firm. When handled or damaged, the flesh of some specimens may bruise a yellow, brown, or pinkish color, especially along the margin.
Gills: The gills of this species are free from the stem apex but close to the stem, crowded, broad near cap margin, and tapering toward stem. The gills are white at first and usually become buff, pinkish, or dingy grayish at maturity. The edges of the gills are delicately fringed when viewed under a lens.
Stem: The stem of Leucoagaricus leucothites measures 5-15 cm in length and is 0.5-1.5 cm in thickness. The stem is usually club-shaped with a slightly enlarged base and a tapered apex and is usually hollow at maturity. The color of the stem is white throughout and may become yellow or brown with age, while the surface of the stem is dry and smooth.
Veil & Ring: The partial veil leaves behind a distinct, persistent, superior, double-edges, collar-like white ring on the upper stalk. The ring may sometimes become moveable.
Spore: The spores of this species measure 7.5-11 x 5-6.5µm. They are colorless, ovoid, smooth, and thick-walled with a small apical pore. The spores are also dextrinoid, turning a red-brown color when Melzer’s iodine solution is applied.
Spore Print: The spore print of Leucoagaricus leucothites is white.
Edibility and Flavor: The species is considered edible and most mycological literature lists it as a “choice edible”. However, consumption of this species IS NOT RECOMMENDED. The recommendation against consumption is derived from two factors. The first comes from the selective sensitivity of some individuals to Leucoagaricus leucothites, in whom the consumption of this mushroom causes gastrointestinal upset. As a matter of fact, some mycological sources claim that L. leucothites is one of the most frequent causes of mushroom poisoning in the Pacific Northwest. The second comes from the very close similarity to several white species of Amanita which can be carelessly confused for it leading to fatal poisonings.
Smell: Leucoagaricus leucothites does not have a distinctive odor.
Habitat: This species is saprotrophic, growing alone or gregariously in grassy areas or on disturbed ground such as pastures, lawns, roadsides, and cultivated areas. Some specimens are known to occasionally form fairy rings. They are also commonly associated with conifers, and commonly grown in their vicinity.
Fruiting Season: Leucoagaricus leucothites fruits from late summer through fall. In Northeastern America, the appearance of L. leucothites is said to mark the beginning of the fall mushroom season. Occasionally specimens may be encountered in the spring and early summer as well.
Range: This species is widely distributed throughout Europe and North America. In the United States they are found in most states, but most commonly in Midwestern and Northeastern states such as Michigan, Ohio, Pennsylvania, New York, Connecticut, Vermont, Maine, and the like.
The Smoothcap Parasol (L. leucothites) can easily and frequently be mistaken for several species of the Destroying Angel (ie. Amanita virosa, Amanita verna, Amanita ocreata). Due to the fact that the probability of misidentification is very high where this mushroom is concerned and in this case, it is very dangerous and can lead to fatal poisoning, L. leucothites should not be collected for the table.
There are several markers that can be used to distinguish between these two species in the field. First, L. leucothites lacks a cup/volva at the base of its stalk, where as Amanitas/Deathcaps all have the base of their stalk is sheathed with a membranous tissue, which is the “cup” or volva. A word of caution, if Amanitas are pulled from the soil, the cup is often left behind. As such, it is important to dig, not pull, these mushrooms from the soil. Additionally, the staining reaction of L. leucothites is also an important identifying field marking.
Various Agaricus species can also be confused with L. Leucothites. However, gills in Agaricus species start out white or light pink, but they turn a dark purplish brown or chocolate brown color as they reach maturity. This differs from the gills of L. Leucothites, which stay white throughout their lifespan.
Another poisonous species that may be confused for L. leucothites is Chlorophyllum molybdites, or the Green-Spored Parasol mushroom. However, C. molybdites has a green spore print, brown scales on its cap, and a much more conspicuous ring on its stem. Additionally, the Green-Spored Parasol prefers a much hotter climate found in Southern and Southwestern United States such as California and the Central Valley
Toxicity of Leucoagaricus leucothites[v]
As mentioned, Leucoagaricus leucothites can cause gastrointestinal upset in susceptible individuals when consumed. Additionally, some mycological sources claim that gray specimen variants are more commonly associated with gastrointestinal upset.
The symptoms of GI upset are reported to start between 10 minutes to 10 hours, with an average of 4 hours, after ingestion of the mushroom. They are characterized by abdominal cramping, diarrhea, nausea, and vomiting.
[i] McKnight, K. H., & McKnight, V. B. (1998). Smoothcap parasol. In A Field Guide to Mushrooms, North America (pp. 243–244). Houghton Mifflin.
[ii] Kuo, M. (2015, July). Leucoagaricus leucothites. Retrieved from the MushroomExpert
[iii] D. Arora (1986) Lepiota naucina (Smooth Parasol; Woman On Motorcycle) In “Mushrooms Demystified: A Comprehensive Guide to the Fleshy Fungi,” Ten Speed Press, Berkeley (p. 300.)
[iv] Davis, R. M., Sommer, R., & Menge, J. A. (2012). Leucoagaricus leucothites. In Field Guide to Mushrooms of western North America, University of California Press. (pp. 89-90).
[v] Lincoff, G. (1981). Smooth Lepiota. In National Audubon Society Field Guide to North American mushrooms (pp. 519-520). Knopf.