Poa secunda subsp. juncifolia var. ampla (Merr.) Soreng, comb. et stat nov.

Soreng, Robert John & Gillespie, Lynn J., 2018, Poa secunda J. Presl (Poaceae): a modern summary of infraspecific taxonomy, chromosome numbers, related species and infrageneric placement based on DNA, PhytoKeys 110, pp. 101-121 : 111

Poa secunda subsp. juncifolia var. ampla (Merr.) Soreng, comb. et stat nov. Figs 1B, C , 3A

Basionym.

Poa ampla Merr., Rhodora 4(43): 145, 1902.

Synonyms.

Poa ampla Merr., P. confusa Rydb., P. juncifolia var. ampla (Merr.) Dorn, P. laeviculmis T.A. Williams, P. truncata Rydb.

Habitat and range.

Open upland forests, mountain steppe, generally in light, well-drained soils to somewhat heavy soils. Range of the subspecies (Fig. 2B ), but mostly absent from west side of the Sierra Nevada and westwards. Minor outlying occurrences in Arizona and New Mexico of subsp. juncifolia (Fig. 2B ) mostly represent var. ampla ( Soreng 1985), likely introduced by seeding.

Chromosome numbers.

Numbers reported as P. ampla : 2 n = 61, 62(x3), 63 (x11), ≈ 63 (x3), 63-64 (x2), 64 (x6), ≈ 65, 70-71, ≈ 97, ≈ 100.

Figures

Figure 1. Poa secunda habit and panicles: A P. s. subsp. secunda var. secunda (Soreng 9359) B P. s. subsp. juncifolia var. ampla (Soreng 9358) C Panicles of subsp. secunda var. secunda (left) and juncifolia var. ampla (right) (Photos. RJS, Deschutes River near Madras, Jefferson Co., Oregon).

Figure 2. Distribution of Poa secunda subspecies in North America: subsp. secunda (yellow); subsp. juncifolia (blue).

Figure 3. Bayesian 50 % majority rule consensus trees of Poa based on plastid (trnT-trnL-trnF, rpoB-trnC, MatK) data (left) and nrDNA ITS and ETS data (right). Bayesian posterior probabilities are shown above branches, maximum parsimony bootstrap values below branches. Outgroups are not shown. Major clades are indicated by colour and capital letters. Taxa shown in blue belong to P. subg. Secundae; those in grey are other taxa of putative hybrid origin that belong to different major clades in plastid and nrDNA trees.