Identification notes
This rather enigmatic moss probably flies under the radar in some areas, including the south, where some bryologists may be unfamiliar with it. It has also gone by other names in the past, including G. retracta, G. subsquarrosa and G. trichophylla var. subsquarrosa.
In the field, candidate plants can be recognised by a particular combination of characters, the best of which is the tendency for the moist leaves to be strongly recurved to squarrose in a very un-Grimmia-like way. Shoots are often darkly coloured and have hyaline hairpoints of variable length, They can be mistaken for Racomitrium species initially but of course lack the characteristic linear sinuose-nodulose basal cells of that genus.
G. lisae currently does not have an account in the Field Guide. More information and contemporary keys are available from the Resources pages. A very important character is the costa section at the extreme leaf base, which has at least 6 guide cells in one layer, separating it from lookalikes such as G. trichophylla and G. dissimulata. Care must be taken to section the leaf in the right place – higher up the leaf the costa has 4 guide cells. There are various ways to get a good section (which all involve using a brand new razorblade) but one recommendation is to slice across a dry shoot, starting at a point where at least one leaf is close to insertion, and continuing to slice thin sections back down the leaf to the very base or beyond. Often, you will then see one or more leaf sections at insertion still encircling a cross-section of the stem on your slide.
