Limacella sect. Limacella is generally considered to contain those and only those species of the genus Limacella that have
(a) "dry" or "non-slimy" stipes [distinguishing this character state is not yet precisely defined]
(b) all terminal cells of gluten-supporting hyphae not conical and not arising from hyphae with intercalary inflated cells
(c) the ratio of length to maximum width for such terminal cells is [roughly...and that's a problem] < 20.
As implied by inserted comments in the above: There are at least two problems with the definition:
1) we lack a good operational definition for a "dry" or "nonslimy" stipe
2) the "nonslenderness" of the terminal cells of the gluten-supporting hyphae on the pileus is not precisely bounded above. This can be stated as follows for the 32 species for which data is available: Length:maximum width ratios for terminal cells of gluten supporting hyphae between 20 and 11 occur in 8 (eight) taxa; and of these 4 (four) are currently considered to be in sect. Limacella and 4 (four) are currently considered to be assignable to sect. Lubricae—the wet or slimy stemmed species.—R. E. Tulloss