Flora of North America species comparison

Species 800–1000 (12 in the flora).

The occurrence of an additional species, not included in the account below, has recently been recognized. This is Alchemilla acutiloba Opiz naturalized near St. John's, Newfoundland. In the key below, it would most likely be identified as A. monticola. It is most readily distinguished by its almost triangular leaf lobes with straight sides and acute triangular teeth. It has yellowish green to grass green leaves. Unlike A. xanthochlora, the adaxial leaf surface is hairy but much less so than that of A. micans or A. monticola. In addition, it differs from A. micans in the rounded hypanthium base and in the stipules being only slightly wine red suffused, and from A. monticola by the hypanthium being glabrous or rarely sparsely hairy proximally.

The majority of Alchemilla species, including all those in the flora area, are agamospermic, high polyploids (to 28-ploid). Most occurrences in North America are as naturalized introductions. Only four species, restricted to Greenland, St. Pierre and Miquelon, and Atlantic coastal regions of Canada, may be native. Some of the introduced species that occur as scattered meadow and hedgerow plants in their native range grow in eastern Canada in large patches as aggressive weeds.

The name Alchemilla vulgaris Linnaeus, used in some North American accounts, was applied in a broad sense to include all the species of sect. Alchemilla, those being all the species occurring in the flora area except A. alpina (sect. Alpinae Camus) and A. mollis and A. venosa (sect. Erectae Fröhner). The type of A. vulgaris represents a mixture of A. glaucescens and A. wichurae (both with very limited occurrences in North America) and the name now is either informally rejected as confused or applied, also informally, in an aggregate sense.

The commonly cultivated species of Alchemilla all fall within sect. Erectae, distinguished from sect. Alchemilla (A. vulgaris of authors) by the epicalyx bractlets being as long as the sepals and almost as wide. In addition to A. venosa, well established on Cape Breton Island and sporadically elsewhere in Atlantic Canada, A. mollis and A. speciosa Buser are in cultivation, the former widely so and recently reported as naturalized. These species are distinguished from A. venosa by their flat or only slightly undulate, densely pubescent leaves. Alchemilla speciosa differs from A. mollis by its pubescent pedicels and its epicalyx bractlets narrower than the sepals.

Aphanes, the members of which are readily distinguished by their annual habit, has sometimes been included in Alchemilla in North American floras and manuals. Over the past half century, the two genera have generally been maintained as distinct, a pattern set even earlier in North America by P. A. Rydberg (1908). As a result of molecular studies, B. Gehrke et al. (2008) have suggested that Alchemilla should be circumscribed more widely to include Aphanes and also Lachemilla (Focke) Rydberg, which occurs in Mexico, Central America, and South America. Both of these genera are shown to be monophyletic groups, as is Alchemilla apart from the African species currently placed in it that form a clade separate from the genus as represented in Eurasia and North America. The African species deserve more thorough investigation before incorporating within Alchemilla such a morphologically distinct genus as Aphanes.

M. J. M. Christenhusz and S. M. Väre (2012) have proposed 35 new names and combinations in Potentilla for those species of Alchemilla and Aphanes native or cultivated in the Nordic countries. This is said to be based on the molecular findings of C. Dobeš and J. Paule (2010), which support previous results by T. Eriksson et al. (1998). These studies note that when Potentilla is traditionally circumscribed (as for example by P. W. Ball et al. 1968), it is paraphyletic and Alchemilla is nested within it, leading Chistenhusz and Väre to adopt an inclusive Potentilla that Dobeš and Paule consider an impractical and unconventional generic circumscription, a view that the authors share. As laid out by B. Ertter (2007), in this flora the authors follow the alternate option taken by Dobeš and Paule and other authors (A. Kurtto and Eriksson 2003; J. Soják 2008) of regcognizing within the monophyletic subtribe Fragariinae not only Alchemilla, Chamaerhodos, and Fragaria, but also other genera previously segregated from Potentilla on morphological grounds, such as Comarum, Dasiphora, Drymocallis, Farinopsis Chrtek & Soják, Sibbaldia, and Sibbaldiopsis.

(Discussion copyrighted by Flora of North America; reprinted with permission.)