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GRASSES
OF THE COLUMBIA BASIN OF BRITISH COLUMBIA
Glyceria species are tall, aquatic or marsh perennials that have creeping stems that root at the stem nodes, or have strong rhizomes. The sheaths are closed or partially closed and the leaf blades are flat to slightly inrolled. The flowerheads are open and have long, drooping, fine branches, or the branches are pressed tight to the stem. Whether the lemmas of Glyceria have seven obvious ridges or not, and whether there are rounded or flattened spikelets in the flowerhead, are two major characters used in differentiating the various species in the genus. The name Glyceria comes from the Greek word glukeros meaning sweet, referring to the sweet seed that is favoured by many waterfowl. The species are very palatable but are restricted to wet sites and moist woodlands. In many areas these species, especially Glyceria striata, are grown on wet marshes for grazing or to attract waterfowl. There are eight species of Glyceria found in British Columbia (Douglas et al., 1994). Three of these species are Blue Listed in the Rare Native Vascular Plants of British Columbia by Douglas et al. (1998). Two of these Blue-listed species -- Glyceria leptostachya and Glyceria pulchella -- occur in the Columbia Basin region. Glyceria pulchella is a boreal species and southern British Columbia is the southern extent of the range.
Leaves and Stem: The smooth sheaths are flattened and open for 1-4 cm. Sharply pointed ligules are 5-10 mm long and minutely hairy along the edge. Flat leaves are 3-5 mm wide and covered with small projections that do not feel rough. There are no auricles. Flowerhead and Flowers: The flowerhead is 45 cm long and has branches that are pressed close to the stem axis and point upward. Narrow spikelets have parallel sides and are rounded (flattened cylindrical) rather than compressed. The awnless, papery glumes are transparent and shorter than the lowest lemma. The awnless lemma has seven noticeably rough, raised nerves. These ridges do not converge at the tip but end at the transparent edge. Sometimes short soft hairs occur between the nerves. Similar Species: Northern Mannagrass has a similar flowerhead to the Blue-listed Slender-spiked Mannagrass (Glyceria leptostachya), but there are differences. The leaves of Northern Mannagrass are bumpy but not rough on the upper surfaces, whereas the upper leaves of Slender-spiked Mannagrass are rough. This difference can be determined by rubbing the top of theleaves. Rough feels like sandpaper, whereas bumpy is more irregular bumps. The lemma of Northern Mannagrass has small bumps along the ridges, but is smooth between the nerves. Slender-spiked Mannagrass has rough-feeling hairs throughout the entire surface of the lemma. To distinguish these features you will definitely need a hand lens.
Leaves and Stem: The rough sheath is closed almost to the top. The ragged blunt ligules are 3-6 mm high and are open in the front. There are no auricles. The flat leaf blades are 6-10 mm wide. Flowerhead and Flowers: The flowerhead is loose, open, 15-25 cm long and has spreading branches. The glumes are shorter than the lemmas and are torn along the edge. The lemmas have seven raised ridges with a tip that is ragged and are widest above the middle. The tip of the palea has narrow slits. The palea often appears almost transparent, so inserting a piece of black paper under the palea helps to see the slits clearly. Similar Species: Tall Mannagrass resembles Fowl Mannagrass (Glyceria striata). Tall Mannagrass has ligules that are open in the front and they are 3-6 mm high, whereas Fowl Mannagrass has closed ligules that are only 1-3 mm long. Check the edges of the ligules carefully to see if they are torn.
Leaves and Stem: Smooth to slightly rough sheaths are closed to the top or open up to 1 cm at the most. The ligules are 4-9 mm long, blunt and have edges with almost no teeth. There are no auricles. The flat, firm leaf blades are 6-15 mm wide, and they have a rough upper surface and a smooth underside. Flowerhead and Flowers: The open, loose flowerhead is 20-35 cm long and has numerous spreading branches. Spikelets are slightly flattened and four- to seven-flowered. The glumes are pointed and the second glume is half the size of the first. The lemmas are widest at the middle, obviously seven-nerved, and have a slightly ragged blunt tip. The palea has a V-shaped notch at the tip, or appears jagged. This feature may be difficult to observe. Open the flower over black paper to make the palea more visible. Similar Species: Reed Mannagrass is similar to Tall Mannagrass, but is distinguished by its longer glumes: 1.3-3.5 mm in Reed Mannagrass compared to 0.6-1.5 mm in Tall Mannagrass.
Leaves and Stem: The flattened sheaths are sometimes rough and closed for most of their length, but can be open for 1 cm. Sharp-pointed ligules are 6-11 mm long and rough edged. The leaf blades are 3-7 mm long, slightly inrolled and rough on both surfaces. There are no auricles. Flowerhead and Flowers: The flowerhead is 40 cm long, loose and has a few branches pressed close to the stem axis. Spikelets are long, cylindric and rounded across the back. The short membranelike glumes are 1/2 the size of the lemma. The lemma is greater than 3 mm long, strongly seven-nerved with rough, short, stiff hairs on and between the ridges. The ragged and transparent upper edge of the lemma can be purplish. Similar Species: Slender-spiked Mannagrass resembles Northern Mannagrass, but differs in leaf blade texture, Douglas et al. (1994). Slender-spiked Mannagrass has a rough texture to the upper leaf blades, whereas Northern Mannagrass has a smooth leaf blade.
Leaves and Stem: The open sheath is smooth. Pointed membranelike ligules stand 1.5 mm high. The drooping, flat leaf blades are 2-6 mm wide and are somewhat inrolled. There are no auricles. Flowerhead and Flowers: The flowerhead is usually less than 20 cm long, loose and somewhat drooping. Thin branches are 8-10 cm long. The papery glumes are broad toward the top, greater than 1.0-1.5 mm long, and pale purplish brown or whitish and transparent. Glumes are almost as long as the first lemma and have ragged tips. The awnless lemmas are rough and have broad, ragged margins. Similar Species: Slender Mannagrass is one of the three Glyceria species that is Blue Listed in British Columbia (Douglas et al., 1998). It resembles Reed Mannagrass, but the plant is smaller, less stout and fewer flowered. It may be also confused with Fowl Mannagrass (Glyceria striata), which has <1-mm-long glumes and small lemmas.
Leaves and Stem: The rough sheath is closed for most of its length and may have a purplish base. The membraneous ligules are usually closed in front, but may split. Looking along the edge of the sheath, you may notice a lighter line, which will split if pressure is applied to it. The blunt ligules are 1-3 mm long, and have a rough or bumpy surface and ragged edges. The leaf blades are flat to folded and 2-5 mm wide. Flowerhead and Flowers: The flowerhead is 7-25 cm long, loose and has slender upward-pointing branches. If the flowerhead is immature the branches may appear to be pressed towards the stem axis. If part of the flowerhead is still enclosed in a sheath, then the flowerhead is immature and it will assume a more spreading form with maturity. The spikelet appears oval in outline. The < 1-mm-long glumes are minutely hairy with rough, jagged margins. The first glume is twice as long as the second, and this will help distinguish this species from Tall Mannagrass and Slender Mannagrass. The broad lemmas are barely 2 mm long, and have seven nerves -- they are clearly visible without a hand lens. Similar Species: Fowl Mannagrass resembles Tall Mannagrass, but it has 1-3-mm-long ligules, whereas Tall Mannagrass has 3-6-mm-long ligules. Fowl Mannagrass is also often mistaken for Reed Mannagrass, which has coarser leaves. Reed Mannagrass has distinct cross-ridges in the leaves, especially close to the leaf collar on the sheath and leaf blade. The leaf blades of Fowl Mannagrass are 2-5 mm wide, and considerably more narrow than the leaf blades of Reed Mannagrass; but be careful if using the leaf blade as a determining factor, as you may have an immature specimen of Reed Mannagrass.
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Copyright © Royal
BC Museum |
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Habitat: Slender Mannagrass occurs commonly in Boreal North
America. The Columbia Basin region includes the south limit of its
range. Douglas et al. (1994) excluded it from the Vascular
Plants of British Columbia, but included it in Rare Native
Vascular Plants of British Columbia (1998) as a Blue-listed
species, based on one historic record in the Columbia Basin region
near Columbia Lake. There are no specimens of Slender Mannagrass
at the Royal British Columbia Museum from the Columbia Basin region.