page_title: Lactarius indigo
section_title: Microscopic features
hierarchical_section_title: Lactarius indigo / Description / Microscopic features
caption_attribution_description: English: The edible mushroom Lactarius indigo (Schwein.) Fr. Photographed in Jalisco, Mexico. "Notes: I ate these for dinner. They were very good."
context_page_description: Lactarius indigo, commonly known as the indigo milk cap, the indigo lactarius, or the blue milk mushroom, is a species of agaric fungus in the family Russulaceae. A widely distributed species, it grows naturally in eastern North America, East Asia, and Central America; it has also been reported in southern France. L. indigo grows on the ground in both deciduous and coniferous forests, where it forms mycorrhizal associations with a broad range of trees. The fruit body color ranges from dark blue in fresh specimens to pale blue-gray in older ones. The milk, or latex, that oozes when the mushroom tissue is cut or broken — a feature common to all members of the genus Lactarius — is also indigo blue, but slowly turns green upon exposure to air. The cap has a diameter of 5 to 15 cm, and the stem is 2 to 8 cm tall and 1 to 2.5 cm thick. It is an edible mushroom, and is sold in rural markets in China, Guatemala, and Mexico.
context_section_description: When viewed in mass, as in a spore print, the spores appear cream to yellow colored. Viewed with a light microscope, the spores are translucent (hyaline), elliptical to nearly spherical in shape, with amyloid warts, and have dimensions of 7–9 by 5.5–7.5 μm. Scanning electron microscopy reveals reticulations on the spore surface. The hymenium is the spore-producing tissue layer of the fruit body, and consists of hyphae that extend into the gills and terminate as end cells. Various cell types can be observed in the hymenium, and the cells have microscopic characteristics that may be used to help identify or distinguish species in cases where the macroscopic characters may be ambiguous. The spore-bearing cells, the basidia, are four-spored and measure 37–45 μm long by 8–10 μm wide at the thickest point. Cystidia are terminal cells of hyphae in the hymenium which do not produce spores, and function in aiding spore dispersal, and maintaining favorable humidity around developing spores. The pleurocystidia are cystidia that are found on the face of a gill; they are 40–56 by 6.4–8 μm, roughly spindle-shaped, and have a constricted apex. The cheilocystidia—located on the edge of a gill—are abundant, and are 40.0–45.6 by 5.6–7.2 μm.
caption: The "milk", or latex, is indigo blue.
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