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GRASSES OF THE COLUMBIA BASIN OF BRITISH COLUMBIA Heather Stewart, Richard Hebda Major Groups of Grasses Table of Contents Glossary Agrostis Bentgrasses The name of the genus Agrostis derives from a Greek word for grass and is the basis of the name for the study of grasses called Agrostology. Bentgrasses are common meadow, pasture and lawn grasses because they are included in seed mixtures. There are also several native species. The Columbia Basin region has at least seven species of Agrostis growing in it. Typical features include very small one-flowered spikelets that separate from the stem above the glumes at maturity. The lemmas are equal to, or much smaller than, the glumes. The sheaths are open and the ligules are membranelike. Leaves vary from flat to folded and inrolled. The flowerhead is branched and relatively open to fully open, not spikelike (except in Agrostis exarata). The branches of the flowerhead do not droop. In Agrostis there are no obvious stiff hairs at the base of the lemma, whereas in the closely related Calamagrostis (Reedgrass) there are. Two groups of Agrostis occur in the Columbia Basin region. One group has stolons (above-ground horizontal stems) or rhizomes (below-ground or at-ground root-stems) and includes only introduced species including Agrostis capillaris, A. gigantea and A. stolonifera. The second group generally lacks stolons or rhizomes. If rhizomes or stolons are present they are < 2 cm long. This group contains native species of naturally open sites especially at high elevations. To identify native species you will need a hand lens or dissecting microscope because many of the distinguishing features are small. For example, to identify whether you have Agrostis humilis or Agrostis variabilis you must determine whether or not there is a palea. A. variabilis either has a rudimentary palea or no palea at all. Heights of Agrostis species. Agrostis- Adapted from Douglas et al. (1994)   1a. Rhizomes or stolons absent............................................2   2a. Flowerhead open with branches spreading; has very few spikelets on lower ½ of the branches; palea absent or less than ¼ as long as lemma .......................................................................................................................................Agrostis scabra   2b. Flowerhead constricted or with branches pressed close to the axis; branches may barely be visible..........................3 3a. Palea present, ½ as long as lemma. Plants of subalpine and alpine zones .......................................................................................................................................Agrostis humilis   3b. Palea absent, if present a minute membrane......................................4 4a. Lemmas awnless ..............................................................................................Agrostis variabilis   4b. Lemmas awned from the back............................................................................Agrostis exarata       1b. Rhizomes or stolons present; flowerhead open with branches spreading; very few spikelets on lower ½ of the branches. Palea present, ½ as long as lemma...........................................................................................................................................5   5a. Stolons present, no rhizomes.......................................................................Agrostis stolonifera   5b. Stolons absent, rhizomes present.................................................6   6a. Ligules 2-6 mm; rhizomes abundant and long...............................................Agrostis gigantea 6b. Ligules up to 2mm............................................................................................Agrostis capillaris   Agrostis capillaris L. Colonial Bentgrass Plant: Agrostis capillaris is an introduced species that grows to 20-50 cm tall. It has a short rhizome and is a perennial with a broad, open flowerhead with tiny spikelets. Leaves and Stem: A few short rhizomes can occur within the root mass. The stems are slender with open sheaths. The flat to folded leaves are 2-5 mm wide. Most ligules are 1-2 mm long, and more or less of even height and wider than they are long. There are no auricles. Flowerhead and Flowers: The flowerhead is 5-15 cm long, sparse and very open. The branches are delicate and bear spikelets only toward the ends. The one-flowered spikelets are usually purple. The two almost equal, pointed glumes are relatively large, and as long or longer than the first flower. The lemma is shorter than the glumes and is either awnless or has a short awn. The palea is 1/2 to 2/3 as long as the lemma. Habitat: Colonial Bentgrass grows in lawns, fields, roadsides, meadows and moist open sites. It is a common component of lawn, turf and pasture seed mixes. Similar Species: Creeping Bentgrass (Agrostis stolonifera), another grass used in seed mixtures, has no rhizomes but has stolons. Its ligules are longer (3-6 mm) than those of Colonial Bentgrass. Creeping Bentgrass occurs in moister habitats (ditches, pond edges, moist fields and meadows) than does Colonial Bentgrass. Agrostis exarata Trin. Spike Bentgrass Plant: Agrostis exarata is a native species that grows to 1.2 m, but is usually shorter. It is a tuft-forming perennial with a spikelike flowerhead and mostly erect stems that may root at the lowest nodes. Leaves and Stem: Sheaths are open. Leaf blades are flat, rough and 2-10 mm wide. Ligules are 3-8 mm high and somewhat torn at the tip. There are no auricles. Flowerhead and Flowers: The flowerhead is 5-18 cm long, narrow, spiky and somewhat open. The axis may be exposed between the clusters of branches. The tiny spikelets are generally clustered toward the base of the side branches. The small, nearly-equal glumes are rough on the back and much longer than the first flower. They usually come to a point or have a small awn. There is a single lemma, which may or may not have an awn. If there is an awn, it is attached above the midpoint and may reach 5 mm long. The palea is less than 1/3 the length of the lemma. Habitat: Spike Bentgrass grows at low to mid elevations in moist sites such as rocky beaches, river bars and moist meadows. In the Columbia Basin region it has been collected from Pilot Bay Provincial Park, Nelson and Kokanee Glacier Park. Similar Species: Variable Bentgrass (Agrostis variabilis) is similar to Spike Bentgrass, but it is much smaller and has a tight, but not spikelike, flowerhead that grows to 2-6 cm long. Its leaves are narrow and it grows generally in alpine and subalpine environments. Agrostis gigantea Roth. Redtop Plant: Agrostis gigantea is an introduced species that grows to 1.2 m tall. It is a perennial with numerous rhizomes. The open-branched flowerheads are densely covered in spikelets to the base. Leaves and Stem: One to two stalks arise from the nodes of rhizomes that are 10 cm+ long. Sheaths are open. Leaf blades are flat to folded and rarely > 4 mm wide. Ligules are 2-6 mm high. There are no auricles. Flowerhead and Flowers: The flowerheads are purplish, up to 30 cm long, branched, somewhat narrow and densely covered by one-flowered spikelets. Glumes are almost of equal size and longer than the flower. The lemma is 1/2-2/3 the length of the glumes and is awnless. The palea is .7-1.4 mm long (1/2 the size of the lemma). Habitat: Redtop grows in dry, disturbed sites, fields and roadsides. A large number of specimens have been collected throughout the Columbia Basin region. Similar Species: Redtop differs from Colonial Bentgrass by having ligules that are longer than they are wide. Redtop differs from Creeping Bentgrass by having rhizomes, and an open flowerhead. Agrostis humilis Vasey Agrostis thurberiana auct. non A.S Hitchc. Alpine Bentgrass Plant: Agrostis humilis is a native species that grows to 15 cm tall. It is a tuft-forming perennial with a small, narrow flowerhead. Leaves and Stem: Sheaths are open and there are no auricles. The short extremely narrow (1 mm) leaves form a tuft at the base. Leaves are flat to folded and smooth. The ligule is 0.5 to 1 mm long and somewhat toothed. Flowerhead and Flowers: The flowerhead is deep purple, and usually .5 cm wide and 1.5-2.5 cm long. There are two more-or-less-equal glumes that are 2 mm long and enclose a single lemma of about the same length. The palea is 1-1.5 mm long. Habitat: Alpine Bentgrass grows in subalpine to alpine meadows and streambanks. It can be found at Kokanee Glacier Provincial Park and Mount Revelstoke National Park in the Columbia Basin region. Similar Species: Alpine Bentgrass is similar to Variable Bentgrass (Agrostis variabilis), except that Variable Bentgrass has no palea. Agrostis scabra Willd. Hair Bentgrass Plant: Agrostis scabra is a native species that grows to 20-70 cm tall. It is a clump-forming perennial with rough-feeling stems and open-branched drooping flowerheads. Scabra means rough in Latin. Leaves and Stem: The numerous, very fine, short leaves grow mostly at the base. Occasionally short rhizomes or stolons occur. Sheaths are open. Leaf blades are mostly folded and 1-3 mm wide. Ligules are 2-3 mm long and there are no auricles. Flowerhead and Flowers: The flowerhead is purple, open, 15-30 cm, and has rough upward-reaching to drooping branches. The branches, however, are not densely packed at maturity. Single-flowered spikelets occur mostly at the branch tips. The glumes are 2-3 mm long, more or less equal length and much longer than the flower. Lemmas are 1-2 mm long, and may or may not have an awn. If present, the awn is 2 mm long and attached on the middle of the outside. There is no palea. Habitat: Hair Bentgrass grows on dry to moist, disturbed sites such as clearings and roadsides. It also invades dry, rocky slopes and gravel bars. In the Columbia Basin region Hair Bentgrass occurs in Glacier National Park, Yoho National Park, the Flathead area and Trail. Similar Species: Hair Bentgrass has a very open, diffuse flowerhead with branches that sometimes are rather lax and there is no palea. Within the Agrostis genus, Hair Bentgrass looks distinctive, but it can have a superficial resemblance to other genera with an open, diffuse flowerhead, such as Silver Hairgrass (Aira caryophyllea). Agrostis stolonifera L. Creeping Bentgrass Plant: Agrostis stolonifera is an introduced species that grows to 60 cm tall. It is a perennial with has stolons, and a large open-but-narrowed flowerhead. Leaves and Stem: The lower part of the stem reclines against the soil and roots at the nodes (stolon-forming). Sheaths are open. Flat to folded leaf blades are more than 4 mm wide. Ligules reach 3-6 mm. There are no auricles. Flowerhead and Flowers: The flowerhead is openly branched, but somewhat narrowed compared to Colonial Bentgrass. One-flowered spikelets are borne to the base of the branches. The small glumes are nearly equal and longer than the first flower. The tiny lemma is 2/3 to 3/4 the length of the glume. There is usually no awn. The palea is almost equal to the lemma. Habitat: Creeping Bentgrass grows in moist lawns, fields, along ditches and at the margins of salt marshes, ponds and lake shores. In the Columbia Basin region, Creeping Bentgrass occurs at Emerald Lake, Lardeau and Creston. Similar Species: See Colonial Bentgrass (Agrostis capillaris) and Redtop (Agrostis gigantea). Agrostis variabilis Rydb. Variable Bentgrass Plant: Agrostis variabilis is an introduced species that grows to 25 cm tall. It is a tuft-forming perennial with a small, spikelike flowerhead and erect stems. Leaves and Stem: Stems arise from dense masses of basal leaves. Sheaths are smooth and open. There are no auricles. The flat to folded leaves are from 1.0-2.5 cm wide, and range from smooth to rough. Ligules are 0.5-2.5 mm long, and have a torn to slightly hairy margin. Flowerhead and Flowers: The narrow, dense, purple flowerhead is 3-6 cm long and up to 1 cm wide. Spikelets have small nearly equal glumes that are mostly smooth on the back. The usually unawned lemma is slightly shorter to much shorter than the glumes. The palea is 0.2-0.4 mm long, so it is considered as "none". Habitat: Variable Bentgrass grows in subalpine to alpine meadows and on open ridges. This species is known from Lake Windermere, Kokanee Park and Hamilin Lake in the Columbia Basin. Similar Species: There are two species similar to Variable Bentgrass. They are Alpine Bentgrass and Spike Bentgrass. The differences are: Variable Bentgrass has no palea whereas the other two do. Another distinguishing character is that the glumes of Variable Bentgrass are mostly smooth.

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