Flora of North America species comparison

Festuca rubra is interpreted here as a morphologically diverse polyploid complex that is widely distributed in the arctic and temperate zones of Europe, Asia, and North America. Its treatment is complicated by the fact that Eurasian material has been introduced in other parts of the world. In addition, hundreds of forage and turf cultivars have been developed, many of which have also been widely distributed. Within the complex, morphologically, ecologically, geographically, and/or cytologically distinct taxa have been described, named, and given various taxonomic ranks. In some cases, these taxa represent extremes, and in other cases they are morphologically intermediate between other taxa. Moreover, hybridization and/or introgression between native taxa, and between native and non-native taxa, may be occurring. In Iceland and southern Greenland, putative hybrids between Festuca frederikseniae and F. rubra have been reported, and named F. villosa-vivipara (Rosenv.) E.B. Alexeev (see under F. frederikseniae, p. 436).

Overlap in morphological characters between most taxa in the complex has led some taxonomists to ignore the variation within the complex, calling all its members Festuca rubra without qualification. This obscures what is known about the complex, and presents an extremely heterogenous assemblage of plants as a single “species”—or a mega-species. The following account attempts to reflect the genetic diversity of the F. rubra complex in the Flora region. All the taxa are recognized as subspecies, but they are not necessarily equivalent in terms of their distinction and genetic isolation. Much more work on the taxonomy of the F. rubra complex is needed before the boundairs of individual taxa can be firmly established. Some variants that need attention are (1) plants growing on the sandy shores of the Great Lakes that have glaucous leaves and spikelets, sometimes treated as F. rubra var. juncea (Hack.) K. Richt., (2) native plants along the James Bay and Hudson Bay shore that are ecologically distinct from F. rubra subsp. rubra, (3) native plants growing in marshes, sometimes called F. rubra var. megastachys (Gaudin) Hegi (Dore and McNeill 1980), (4) seashore variants along the Atlantic coast of North America, (5) plants with glaucescent leaves and spikelets which are widely distributed in the Flora region and have been called F. rubra subsp. glaucodea Piper, (6) the widespread variant with pubescent to villous lemmas, sometimes called F. rubra f. squarrosa (Hartm.) Holmb.

Festuca earlei (p. 420) is sometimes confused with F. rubra. It differs in having pubescent ovary apices.

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

Festuca subverticillata grows in moist to dry, deciduous or mixed forests with organic rocky soils, from Manitoba to Nova Scotia, south to eastern Texas, Florida, and north-eastern Mexico. Plants that are sparsely pilose over the sheaths and blades have been named F. subverticillata f. pilosifolia (Dore) Darbysh. They frequently grow in mixed populations with F. subverticillata (Pers.) E.B. Alexeev f. subverticillata.

Festuca subverticillata resembles F. paradoxa (see next), but its spikelets are less crowded on the branches.

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