I received an exsiccata collected on the 20-Sep-2021 from a close friend/botanist who found it in a garden and growing close to a stump of a small tree. This was growing during a warm season here in Malta. After initial examination, I am sure that it is a Parasola species. However narrowing to species level is quite uneasy.
First of all, a strange character is the presence of pubescence especially at the base of the stipe (I am used to glabrous stipes for Parasola). Next the pileus lacked the typical thick-walled setae (see images) but there was some kind of hyphae forming free fibrillose tufts on the pileus. The pileus was ribbed, with the ribs being brownish and the furrows being grey. The exsiccata has lost its basidia and most cheilocystidia since the edges had eroded/deliquesced, but I managed to see two large spherical bodies which might represent cheilo-or pleurocystidia, but since being globular, they might be something else. The pileipellis consisted of not very long rectangular to cylindrical hyphae, with truncated ends, sometimes a small branch (foot) and with some pigmented (?) incrustations. The following sizes were measured:
37.1 [56.4; 75.8] 95.2 × 12.6 [17; 21.5] 25.9 µm
Q = 1.5 [2.8; 4.2] 5.6; N = 9; C = 95%
Me = 66.1 x 19.3 µm; Qe = 3.5
The spores are ovoid or almond shaped (depending the plane of view) with a distinct germpore
7.4 [8.8; 9.3] 10.7 × 5 [5.7; 5.9] 6.6 µm
Q = 1.3 [1.5; 1.6] 1.8; N = 40; C = 95%
Me = 9 x 5.8 µm; Qe = 1.6
Caulocystidia or hairs looked as elongated shortly-cylindrical hyphae
After spending considerable time researching, I am seeing P. lactea and P. kuehneri as the best options especially for the small size of the spores.
.Another option a I told him is that the young specimens had remnant veil and got lost with time-transport and hence his specimen might as well be a Coprinopsis.... but for me the pleated shape of the pileus with grey furrows and tawny-brown ribs is indicative of Parasola!