17. Lepiota parvannulata (Lasch: Fr.) Gillet, Hyménomycètes: 66. 1874. - Fig. 93.
Agaricus parvannulatus Lasch in Linnaea 3: 156. 1828; Agaricus parvannulatus Lasch: Fr., Syst. mycol., Ind. gen.: 34. 1832.
SEL. JCON. - Candus-.o &: Lanzoni, Lepiota: pl. 25b. 1990.
SEL. DESCR. & 11(;5. - Kelderman in Coolia 34: 52-53, fig. 2. 1991; Kühner in Bull. trimest. Soc mycol. Fr. 52: 218-219. 1936.
VERN. NAME - Witte dwergparasolzwam.
Pileus 5-25 mm, conve x with low umbo, ochraceous with reddish tinge at centre, cream-colourcd to white at margin, completely cov ered in woolly-tomento-.e fihrils, with sorne toothed velum remnants at margin. Lamellae. L 20-28, 1 = 1-3, crowded, free, subventri cose, white to slightly cream-coloured, with even concolorous edge. Stipe 11-25 X 0.7-3 mm. cylindrical or slightly broadened at base, fis tulose, white, with annulus, below annulus with sorne ochraceous fibrils on white to cream background. Annulus ascending, white, fragile and membranaceous. Context white, in basal part of stipe becoming brownish with age.
Spores 3.5-4.5 x 2.0-3.0 um, Qav = 1.7, non-dextrinoid, not congophilous, not metachromatic in Cresyl Blue, uninucleate. Basidia 14- 20 x 5.0-6.6 um, 4-spored. Lamella edge fertile. Cheilocystidia absent. Pleurocystidia absent. Pileus covering made up of repent to ascending hyphae with terminal elements non- or up to 2-septate (without clamp connections at the sepia), 170-300 X 5-6.5 um, without pigment. Clamp-connections present in ail tissues.
HABITAT & DfSTR. - Solitary to gregarious, saprotrophic and terres trial in a nutrient-rich, relatively warm part of a wooded slope. In the Netherlands very rare, recorded only once from one locality in south em Limburg (Valkenburg. Schaelsberg), Sept. Known from only a very few finds throughout central and mediterranean Europe.
The above description has been based on the selected descriptions cited. The spores of this taxon are uninucleate, while most Lepiota species have binucleate spores. The absence of chemical reaction of the spore wall in Melzers Reagent and Congo Red is also a striking character of this species. Lepiota nigrescentipes G. Riousset (in Bon & G. Riousset in Doc. mycol. 22 (85): 67-68. 1992) cornes very close to L. parvannulata, has also uninucleate spores with the same kind of chemical reactions, but differs in the stipe which hlackens with age. Lepiota parvannulata resembles white Leucoagaricus-species like L. serenus (Fr.) Bon & Boiffard and L. sericifer (Locq.) Vellinga, but the presence of numerous clamp-connections makes it unlikely that this taxon belongs to that genus. Spores of Leucoagaricus-species are binucleate.
