text: mycena californiensis mycena californiensis is a species of fungus in the mycenaceae family . it is a common and abundant species in the coastal oak woodlands of california , where it grows , feeding on the fallen leaves and acorns of various oak species . first described in 1860 by berkeley and curtis , the species was collected four years earlier during an exploring and surveying expedition . it was subsequently considered a doubtful species by later mycena researchers , until a 1999 publication validated the taxon . mycena elegantula is considered a synonym . making their appearance in late autumn to early winter , the small and fragile fruit bodies are characterized by reddish - brown tones in the cap , stem , and the edges of the gills . if cut , the mushroom tissue will " bleed " a deep reddish to orangish latex . as is typical of the genus mycena , caps of m. californiensis are bluntly conical , becoming bell - shaped to convex , and eventually flatten out when old . they measure up to 2 cm ( 0 . 8 in ) in diameter , and are attached to thin , hollow stems that are up to 13 cm ( 5 . 1 in ) long . history and taxonomy the species was originally collected for science purposes by the american botanist charles wright during the north pacific exploring and surveying expedition of 1853 – 56 . the single collection was found growing on fallen oak leaves at mare island naval shipyard , in solano county , california in january 1856 . the specimen was sent by american mycologist moses ashley curtis to his british colleague miles joseph berkeley , who published a brief description of the species in 1860 , calling it agaricus californiensis , in what was then the subgenus mycena . berkeley and curtis noted that it differed from a. - marginatus ( known today as mycena aurantiomarginata ) in the nature of the gills , and they called it " a more graceful species . " in his 1887 sylloge fungorum , pier andrea saccardo raised the subgenus mycena to generic status , so the species became known as mycena californiensis . in his 1947 monograph of north american mycena , alexander h. smith included it as an " excluded or doubtful species " , saying that the species " cannot be recognized until the microscopic characters of the type are known . " researching his 1982 monograph of mycena , maas geesteranus examined the holotype material — the particular specimen designated by berkeley and curtis to represent the type of the species . because of its deteriorated condition , however , he was unable to corroborate the distinguishing features proposed by berkeley and curtis , and he agreed with smith 's assessment of the species . in the late 1990s , as part of his studies on the mycena of california , brian perry noted that a common species in california , usually referred to as mycena elegantula or m. sanguinolenta , presented characteristics not congruent with either ( in particular , m. elegantula had not previously been reported to contain latex ) . he compared isotype material ( material collected at the same time and place as the holotype ) of m. californiensis with californian specimens and the type of m. elegantula and found all of them to represent the same species , publishing the results with dennis desjardin in their 1999 mycotaxon article " mycena californiensis resurrected " . part of the confusion , they noted , was apparently due to smith 's concept of m. elegantula not agreeing with the species ' type ( something also noticed by geesteranus ) . because m. californiensis is the earlier name ( published in 1860 vs. 1895 for mycena elegantula ) , it has priority over the later name m. elegantula , according to the rules of botanical nomenclature . description the cap of m. californiensis is initially conic or bell - shaped , but flattens out in maturity , and typically reaches dimensions of up to 2 cm ( 0 . 8 in ) . the cap margins ( edges ) are curved inwards when young , but as they age they become wavy or crenate ( with rounded scallops ) , develop striations ( radial grooves ) and may even split . the surface of the cap is dull and smooth . its color ranges from reddish - brown to brownish - orange in young specimens , with the color fading as the mushroom matures ; the center of the cap is usually darker than the margins . the flesh is thin , and either the same color as the cap or ; it may stain a dark red color when bruised . the gills have an adnate attachment to the stem — broadly attached slightly above the bottom of the gill , with most of the gill fused to the stem . they are not closely spaced together , and there are about 15 – 20 of them . some of the gills do not extend the full distance from the edge of the cap to the stem . these short gills , called lamellulae , form one to two groups of roughly equal length . all of the gills have a white to pinkish - buff color , with the gill edges ranging from reddish - orange to reddish - brown to brownish - orange . the hollow stem is 29 – 130 mm ( 1 . 1 – 5 . 1 in ) long by 1 – 3 mm ( 0 . 04 – 0 . 12 in ) thick , and roughly the same thickness throughout . the top of the stem may be either pruinose ( appearing to be covered with a very fine whitish powder on a surface ) or smooth , while the stem base is covered with " hairs " that may be strigose ( large , coarse , and bristle - like ) to downy ( soft and fuzzy ) . the stem is some shade of brown . the mushroom tissue will " bleed " a brownish - range to reddish brown latex when it is cut . the edibility of m. californiensis is unknown . microscopic characteristics in deposit , such as with a spore print , the spores appear white . further details are revealed with a light microscope : the spores are ellipsoid to almond - shaped , smooth , thin - walled , and measure 8 – 12 by 4 – 6 µm . the basidia ( the spore - bearing cells ) are club - shaped , four - spored , and typically have dimensions of 26 – 37 . 5 by 7 – 10 . 5 µm . m. californiensis has cheilocystidia ( cystidia on the gill edges ) that measure 16 – 50 by 6 . 5 – 20 µm . these cells have irregular projections that can range in size from 1 . 5 – 18 . 8 by 1 . 5 – 6 . 5 µm and are variously shaped , from knob - like to cylindrical . the cells contain brownish contents that will stain darkly with melzer 's reagent , a common chemical reagent used in mushroom identification . with the exception of the medullary hyphae of the stem ( longitudinally - arranged hyphae making up the stem surface ) , all hyphae contain clamp connections . similar species mycena californiensis may be distinguished from the closely related m. by its smaller size and the purplish tint to the edge of the gills , and from m. purpureofusca by its differently shaped , longer spores . another mycena commonly confused with m. californiensis is m. sanguinolenta , a species that also exudes reddish latex . it can be distinguished from m. californiensis by the fusiform ( tapering at each end ) cheilocystidia that do not have outgrowths . an additional difference between the two is that m. sanguinolenta is associated with conifer wood and debris . habitat and distribution the fruit bodies grow in clusters or scattered on the decomposing leaves and acorns of oak trees , such as coast live oak , valley oak and black oak . it is common in the coastal oak woodlands of california , where it appears from late autumn to early winter .