Poa secunda (variously known by the common names of Sandberg bluegrass, alkali bluegrass, big bluegrass, Canby's bluegrass, Nevada bluegrass, one-sided bluegrass, Pacific bluegrass, pine bluegrass, slender bluegrass, wild bluegrass, and curly bluegrass) is a widespread species of perennial bunchgrass native to North and South America. It is highly resistant to drought conditions, and provides excellent fodder; and has also been used in controlling soil erosion, and as revegetator, often after forest fires. Cultivars include 'Canbar', 'Service', 'Sherman', and 'Supernova'. Historically, indigenous Americans, such as the Gosiute of Utah, have used P. secunda for food. It was originally described botanically in 1830 by Jan Svatopluk Presl, from a holotype collected from Chile by Thaddäus Haenke in 1790.
Subspecies and varieties
Poa secunda is highly variable, and its classification has long been disputed. Many of the forms now placed in it were once treated as separate species. In 1951 C. L. Hitchcock divided it into two groups containing seven species in total. The Flora of North America treats these two groups as subspecies. It notes that they overlap almost completely in their morphology but differ in their ecology and cytology. In 2018 Robert Soreng and Lynn Gillespie divided the species into six varieties in two subspecies, juncifolia and secunda. Under subspecies juncifolia they placed varieties juncifolia, nevadensis and ampla; under subspecies secunda they placed varieties secunda, gracillima and scabrella.
The two subspecies are separated mainly by hairs on the lemmas (the outer bracts of each floret), by how the new shoots branch at the base, by the texture of the leaves, and by the length of the ligules on the new shoots:
Trait
subsp. juncifolia
subsp. secunda
Lemmas
Usually hairless; the keel and marginal veins only occasionally sparsely hairy at the base
Sparsely to densely covered in short hairs over the lower two-thirds
Basal branching
Mainly...
