|
| |||||
|
|
|
GRASSES
OF THE COLUMBIA BASIN OF BRITISH COLUMBIA
The word Elymus is believed to have come from the Greek word for millet, a type of grain. The genus Elymus contains species that are all perennial, have spikelets born singly or occasionally in pairs (up to four in E. canadensis) along an elongated axis. In past interpretations the genus was thought to consist of species in which the spikelets fell off the axis at maturity, but now the genus also includes species with the central axis breaking apart at maturity. Spikelets are laterally flattened and the first glume is usually one half the length of the lowest lemma. The lemmas are rounded on the back or keeled only at the tip. The genus Elymus has been at the centre of taxonomic controversy due in part to the rearrangement of the species in the related genus Agropyron, a genus in the Wheatgrass tribe. For many years grass taxonomists had arranged taxa according to species that were recognized from Europe, and these were compared to what was native to North America. In the last 50 years a great deal of taxonomic work has been done in Russia, Asia and China, and the implication of this work is that a number of species in North America are similar to larger genera that are common in these countries. Initially in moving species out of the Agropyron genus some were placed in the Elymus genus because of similarities to that group. In other instances species were put in new and unfamiliar groups to reflect the global taxonomy. One species that has been part of this taxonomic musical chairs is Elymus repens. E. repens is widespread and well known, but it has a rocky taxonomic history. Hitchcock (1951) placed it in the genus Agropyron. Subsequently it was moved to Elymus and then to Elytrigia to reflect the similarities to other species of Elytrigia in Russia, and now it has been moved back to Elymus (Barkworth, 1999, pers. comm.). In this treatment we call Elymus spicata Pseudoroegneria spicata, to reflect recent changes. These species are not renamed on a whim, but reflect new information from treatments in new floras and an increased understanding of the genetics and population dynamics of grass.
Leaves and Stem: Smooth sheaths are open to the base. The ligules are <0.5 mm long and hairy. The auricles, if they are present, are slender and rarely over 1 mm long. The leaf blades are 2-5 mm wide and flat or slightly inrolled and have scattered hairs. Flowerhead and Flowers: The flowerhead
is a terminal spike about Similar Species: Alaska Wildrye resembles Slender Wheatgrass (Elymus trachycaulus) except that Alaska Wildrye has the widest part of the glumes near the tip and the glume veins are smooth, whereas Slender Wheatgrass has the widest part of the glume near the middle, and the glume veins are rough. This is a character best determined with a hand lens or under a dissecting microscope. Alaska Wildrye has several subspecies in British Columbia, but only two that are found in the Columbia Basin region: latiglumis and alaskanus. About the subspecific level, there is some debate among taxonomists whether ssp. latiglumis should be placed in E. alaskanus ssp. latiglumis or in E. trachycaulis ssp. latiglumis. Barkworth (1999, pers. comm.) feels that the ssp. latiglumis is better placed in the E. alaskanus group. This subspecies is sometimes noted as the Latiglumis/violaceus group, and it includes what was once called Agropyron violaceum.
Leaves and Stem: The mostly smooth sheaths are open to the base. The auricles are usually well developed. Ligules are 0.5-1.5 mm long and finely hairy. The leaves are coarse, arranged along the stem, 5-15 cm wide and may feel smooth to slightly rough to the touch. Flowerhead and Flowers: The spikelike, dense flowerhead is up to 20 cm long and sometimes droopy. There is more than one spikelet at each node and the lower spikelets barely overlap, whereas the upper ones overlap. Glumes are narrow, strongly nerved and broadest below the midlength, sometimes appearing rounded and sometimes slightly flattened. The glume awn is as long as the body of the glume. Glumes are of equal length. Their body is shorter than the first flower. The strongly nerved lemma has short, dense hairs across the back. The awn curves or arches and feels rough to the touch. It is twice as long as the body of the lemma, reaching up to 35 mm in length. Similar Species: Within the genus Elymus there is a split between those species that have one spikelet per node and those that have two or more spikelets per node. Canada Wildrye can have up to four spikelets per node, but varies from plant to plant and even on individual plants; consequently, you should check several nodes before making the decision about how many spikelets are at each node. Blue Wildrye (Elymus glaucus), resembles Canada Wildrye in that it has more than one spikelet per node, but they differ in that the spikelets of Blue Wildrye are narrower than those of Canada Wildrye.
Leaves and Stem: The sheaths are open to the base and the auricles are lacking on some plants and less than 1 mm long on others. The short ligule can be thin with a transparent membrane, or have short hairs and barely reach 0.5 mm high. Leaf blades are flat to folded and inrolled, and 1-4 mm wide. Flowerhead and Flowers: The spike remains partially enclosed in the uppermost sheath, which explains the large length range (3-15 cm). The rachis breaks apart at maturity. Spikelets are commonly two per node, but rarely one or three, so check several specimens. The narrow glumes are awl-shaped, tapering to a sharp point or into one or two 3-10-cm-long awns. The glumes are more or less equal and are shorter than the body of the first flower. The lemma is rough to short hairy with the main nerve and the two lateral nerves extending into awns that are longer than the glume. Similar Species: The flowerhead of Squirreltail Grass takes a range of forms. Sometimes it resembles Elymus characters with two spikelets and four glumes per node. Other specimens have sterile flowers so there appear to be many glumelike spikelets. Douglas et al. (1994) describe two subspecies of Squirreltail Grass -- Elymus elymoides ssp. californicus, with entire glumes that have awns shorter than the lemma awns, and Elymus elymoides ssp. elymoides that has two teeth at the tip of the glume. In ssp. elymoides, the glume awns are longer than the lemma awns.
Leaves and Stem: The sheaths are open, leaf blades flat and lax, mostly 5-10 mm wide. Long, thin auricles are present on most leaves. The ligule is about 1 mm high and arises from a purplish collar. Flowerhead and Flowers: The flowerhead is 5-15 cm long and bears spikelets arranged flatwise to the stem -- mostly two per node but sometimes there is only one. Check several plants when identifying this species. The narrow lance-shaped, nearly equal glumes extend almost to the top of the spikelet, and have three to five distinct nerves. The edges of the glumes are transparent. There are three to five flowers per spikelet. A curved or straight awn extends from the end of the smooth lemma for 1-3 cm, but the awns may be missing in some varieties. Similar Species: In the spring, Blue Wildrye can be determined by the light bluish colour of the leaves (hence the species name glaucous), but later in the season this character is less obvious. See Hairy Wildrye (Elymus hirsutus).
Leaves and Stem: Sheaths are open and there are small or no auricles. Flat leaf blades are 4-10 mm wide. Ligules are only 0.5-1.0 mm high. Flowerhead and Flowers: The flowerhead is 6-15 cm long, flexuous and has spikelets loosely arranged more than one per node. Two narrow, awned glumes are slightly shorter than the flowers and have transparent edges. The awns are 15-25 mm long, protrude from the back of the lemmas and may be straight to slightly curved. There are hairs along the edges of the lemma. Similar Species: This species resembles Blue Wildrye and may interbreed with it. Hairy Wildrye has long hairs along the margin of the lemmas whereas Blue Wildrye does not. The generally more open and flexuous, nodding stem of Hairy Wildrye is somewhat diagnostic. The flowerhead may appear somewhat more bristly than the flowerhead of Blue Wildrye because of the slightly longer awns, but this is difficult to assess unless you have both species in hand.
Leaves and Stem: The sheath is open and is densely covered in minute hairs. The auricles are 1.5 mm long, and the ragged ligules scarcely reach 0.5 mm high. The stiff and inrolled leaf blades are 2-4 mm wide. Flowerhead and Flowers: The stiff and erect flowerhead extends 6-15 cm long. The spike axis does not break apart at maturity. Two spikelets per node contain 4-10 flowers. The oblong to slightly pointed glumes are equal, lightly to strongly hairy and end in a sharp point. The rounded glumes extend slightly more than half way up the first flower. Lemmas are rarely awned and are densely covered in short hairs. Similar Species: Thickspike Wildrye is difficult to tell apart from Western Wheatgrass (Pascopyrum smithii). Both have rhizomes. Western Wheatgrass has a glume that is curved to one side. You can observe this character by carefully observing the midvein of the glume. Barkworth (1999, pers. comm.) has observed hybrids of Thickspike Wildrye and the awned phase of Bluebunch Wheatgrass (Pseudoroegneria spicata).
Leaves and Stem: The open leaf sheath is mostly hairless, but in some cases the lowermost part of the sheath is soft hairy. The flat leaf blade is 2-14 mm wide and somewhat ribbed. The clasping auricles are well developed. Ligules are less than 0.5 mm long and gnawed or short haired. Flowerhead and Flowers: The flowerhead is stiff and erect and approximately 7-15 cm long. There is one spikelet per node attached directly to the stem without a stalk, and these are alternately arranged. The spikelets are closely crowded and twice as long as the internodes. The glume tip is sharply pointed to blunt, and the glumes are stongly keeled. Glumes are more or less equal and shorter than the first flower. The spike axis does not break apart at maturity. The lemmas can be awnless, or awn-tipped with an awn up to 10 mm long. The lemmas are slightly longer than the glumes. Similar Species: Quackgrass is also called Agropyron repens, and is very similar in appearance to Ryegrass (Lolium perenne). Ryegrass has only one glume, whereas Quackgrass has two glumes. One quick visual way to distinguish the two is that Quackgrass has the back of its spikelet (longest side) centred along the axis of the spike, whereas in ryegrass species, the edge of the spikelet (narrow side) is oriented along the axis. Quackgrass might be confused with Slender Wheatgrass (Elymus trachycaulus). Slender Wheatgrass is a tufted native species that lacks auricles (or has very small ones) and does not have rhizomes.
Leaves and Stem: The open sheath is hairless to slightly hairy and the auricles are less than 1 mm long. The ligules are smooth-margined or hairy along the edge and less than 0.5 mm high. The flat or inrolled leaves are 1.5-6 mm wide and can have scattered hairs on the upper surface. Flowerhead and Flowers: The spikelike flowerhead is 4-20 cm long, bearing three to six flowers per spikelet. There is one spikelet per node. The glumes are almost as long as the spikelet, lance-shaped, widest at the middle, and transparent along the margins, with a sharp point and a short awn. The lemmas are smooth or have short hairs and can have awns or not. Similar Species: Slender Wheatgrass forms fertile hybrids with Alaska Wildrye and Thickspike Wildrye. Douglas et al. (1994) have separated two subspecies based on whether the lemmas have awns or not. Lemmas with 10-30-mm-long awns indicate ssp. subsecundus. Lemmas without awns or awns less than 10 mm long characterize ssp trachycaulus. Barkworth (1993) in annotating Slender Wheatgrass specimens at the Royal British Columbia Museum, has attached a note to the sheets describing awned specimens of Slender Wheatgrass as occurring only in locations where other awned species, such as Squirreltail Grass, Blue Wildrye and Foxtail (Hordeum jubatum) occur. She suggests that Slender Wheatgrass is an artificial taxon. Alaskan Wildrye differs from Slender Wheatgrass by having glumes that tend to be widest beyond the middle, and have transparent margins that widen until just before the tip.
|
 |
||
 |
Copyright © Royal
BC Museum |
|
