Four-bladed starfish (Geastrum quadrifidum)

Systematics:
  • Division: Basidiomycota (Basidiomycetes)
  • Subdivision: Agaricomycotina (Agaricomycetes)
  • Class: Agaricomycetes (Agaricomycetes)
  • Subclass: Phallomycetidae (Velkovye)
  • Order: Geastrales (Geastral)
  • Family: Geastraceae (Geastraceae or Stars)
  • Genus: Geastrum (Geastrum or Zvezdovik)
  • Type: Geastrum quadrifidum (Four-bladed starfish)
  • Four-section star
  • Geastrum four-lobed
  • Four-section star
  • Geastrum four-lobed
  • Earth star four-bladed

Description

Fruiting bodies are initially closed, spherical, about 2 cm in diameter, covered with peridium, over the entire surface of which mycelial strands are located; mature – opened, 3-5 cm in diameter. The peridium is four-layered, consisting of exoperidium and endoperidium. The exoperidium is in the form of a cup, three-layer or two-layer, solid, torn from top to bottom to the middle into 4 unequal, pointed parts (blades), bending down, and the fruiting bodies rise up on the lobes, as on “legs”. The outer mycelial layer is whitish, felty, covered with soil particles, and soon disappears. The middle fibrous layer is white or isabella, smooth. The inner fleshy layer is white, also torn into 4 parts, resting with sharp ends on the sharp ends of the lobes of the outer layer, and soon disappears. The base is convex. The middle rises up along with the inner part of the fruiting body – the gleba. Spherical or oval (ovoid) gleba covered with endoperidium, 0,9-1,3 cm high and 0,7-1,2 cm wide. At the base with a flattened stalk, above which the endoperidium is narrowed and a well-marked rounded protrusion (apophysis) is formed, at the top it opens with a hole, which is equipped with a low peristome. The peristome is cone-shaped, fibrous, with a sharply limited courtyard, smoothly fibrous-ciliate, around which there is a clear ring. Leg cylindrical or slightly flattened, 1,5-2 mm high and 3 mm thick, whitish. The column is cotton-like, light brown-gray in section, 4-6 mm long. Its exoperidium is torn more often into 4, less often into 4-8 unequal pointed lobes, bending down, which is why the entire fruiting body rises up on the lobes, as if on legs.

The leg (in the traditional sense) is missing.

Gleba when ripe powdery, black-purple to brown. Spores are brown, light or dark brown.

When pressed, the spores scatter in all directions. Spores are olive brown.

HABITAT AND GROWTH TIME

The four-lobed starfish grows mostly on sandy soil in deciduous, mixed and coniferous – pine, spruce, pine-spruce and spruce-broad-leaved forests (among fallen needles), sometimes in abandoned anthills – from August to October, rarely. Recorded in Our Country (European part, Caucasus and Eastern Siberia), Europe and North America. We found it southeast of St. Petersburg in a mixed forest (birch and spruce) under an old spruce on needles in early October (mushrooms grew as a family).

DOUBLES

The four-lobed starfish is very peculiar in appearance and is strikingly different from mushrooms of other genera and families. It looks like other starlets, for example, the arched starfish (Geastrum fornicatum), whose exoperidium splits into two layers: the outer with 4-5 short, blunt lobes and the inner, convex in the center, also with 4-5 lobes; on Geastrum crowned (Geastrum coronatum) with a leathery, smooth exoperidium, splitting into 7-10 gray-brown pointed lobes; on Geastrum fimbriatum with exoperidium, which is torn to half or 2/3 – into 5-10 (rarely up to 15) unequal lobes; on the Starfish striped (G. striatum) with exoperidium, torn into 6-9 lobes, and light gray gleba; on the small Shmiel’s Starfish (G. schmidelii) with exoperidium forming 5-8 lobes, and a gleba with a beak-shaped, furrowed, striped nose; on Geastrum triplex with a fibrous hole at the top of a gray-brown gleba.

It is confined to the soils of deciduous and coniferous forests.

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