Poa secunda subsp. secunda var. secunda

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 : 112-113

Poa secunda subsp. secunda var. secunda Figs 1A, C , 4F, G

Synonyms.

Aira brevifolia Pursh, Aira missurica Spreng. ex B.D. Jacks., Airopsis brevifolia (Pursh) Roem. & Schult., Atropis canbyi (Scribn.) Beal, Atropis laevis Beal, Atropis laevis var. rigida Beal, Atropis tenuifolia Thurb., Atropis tenuifolia var. stenophylla Vasey ex Beal ( incurva form), Festuca oregona Vasey, Festuca patagonica Phil., Festuca spaniantha Phil., Glyceria canbyi Scribn., Panicularia nuttalliana Kuntze, Poa andina Nutt. ex S. Watson, Poa buckleyana Nash, Poa buckleyana var. buckleyana , Poa buckleyana var. elongata (Vasey) M.E. Jones, Poa buckleyana var. sandbergii (Vasey) M.E. Jones, Poa buckleyana var. stenophylla (Vasey ex Beal) M.E. Jones, Poa canbyi (Scribn.) Piper, Poa fulvescens Trin., Poa gracillima var. saxatilis (Scribn. & T.A. Williams) Hack., Poa helleri Rydb., Poa incurva Scribn. & T. A. Williams, Poa laevigata Scribn., Poa laevis Vasey, Poa leckenbyi Scribn., Poa lucida Vasey, Poa nevadensis var. laevigata (Scribn.) M.E. Jones, Poa nevadensis var. leckenbyi (Scribn.) M.E. Jones, Poa sandbergii Vasey, Poa saxatilis Scribn. & T.A. Williams (toward gracillima form), Poa secunda var. elongata (Vasey) Dorn (= canbyi form), Poa secunda var. incurva (Scribn. & T.A. Williams) Beetle, Poa secunda var. stenophylla (Vasey ex Beal) Beetle, Poa stenantha var. sandbergii (Vasey) B. Boivin, Poa tenuifolia Buckley, Poa tenuifolia Nutt. ex S. Watson, Poa tenuifolia var. elongata Vasey, Poa tenuifolia var. oregona (Vasey) Vasey, Poa wyomingensis Scribn., Puccinellia canbyi (Scribn.) Ponert, Puccinellia laevis (Beal) Ponert

Notes.

There are various variety names included in the autonymic var. secunda . Variety sandbergii is secunda s.s.; vars. elongata , leckenbyi , laevigata and rigida represent the canbyi form; and vars. incurva , saxatilis , buckleyana and stenophylla represent the incurva form. Varieties incurva and saxatilis are generally subalpine to alpine with slightly open panicles; Hitchcock (1951) included them within P. gracillima , but Keck (1959 and annotations) treated them as P. incurva . Vars. buckleyana and stenophylla are intermediate to var. scabrella , but are too smooth to be included in the latter variety. Hitchcock (1951) equated stenophylla with var. gracillima , but we agree with Keck (Suppl. material 2) in equating it with the incurva form. Poa tenuifolia Nutt. ex S. Watson (1871), nom. illeg., was described from heterogeneous original material (at US, distributed as S. Watson 1318): E. Humboldt Mts. = var. juncifolia ; Virginia Mts. = var. secunda ; Diamond Mts. = var. scabrella . However, Watson also cited " Poa tenuifolia Nutt., ms. In Herb." The Nuttall specimen with that name is at PH (PH00020091) and P. tenuifolia Buckley (1862) is based on that specimen. Therefore, Watson’s taxon name is superfluous.

Habitat and range.

Open forests, steppe, and alpine, generally in light, well-drained soils. Range of the subspecies (Fig. 2B ), but mostly replaced by var. scabrella on west side of the Sierra Nevada and westwards and in the Mojave Desert.

Chromosome numbers.

Numbers reported as P. secunda and avowed synonyms: 2 n = 42, 56, ≈ 68, 70 (x2), ≈ 70 (x2), ≈ 74, ≈ 78 (x2), 81, 81, 82 (x2), 84 (x2), 84-88+II, ≈ 84, 85-87, 86 (x2), ≈ 87, ≈ 99, 104. The one count of 2 n = 42 was reported by Bowden (1961) originated from Alberta. Numbers originally reported as P. canbyi : 2 n = 56, 70 (x4), ≈ 72, ≈ 82 (x2), ≈ 83, 84 (x4), ≈ 84 (x2), 85, ≈ 86. Keck (in Munz 1959) attributed higher numbers to P. incurva ). Numbers secondarily reported as P. incurva : 2 n = 90, 93, 94, 99, 105-106.

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 4. Poa secunda infraspecies illustrations (reproduced from Hitchcock 1935): A P. s. var. ampla panicle and floret B P. s. var. juncifolia panicle and floret C P. s. var. nevadensis panicle and floret D P. s. var. gracillima habit, panicle and floret E P. s. var. scabrella habit, panicles, spikelet and floret F, G P. s. var. secunda habit, panicle and floret variations A, B, C = subsp. juncifolia D, E, F, G = subsp. secunda. Scale bar: 5 mm for florets, 10 mm for spikelet, 5 cm for habits and panicles (10 cm for E habit and panicles).