Wheatgrasses of Wyoming By A. A. Beetle Wyoming Agricultural Experiment Station September 1955 Bulletin 336 Wheatgrasses of Wyoming By Alan A. Beetle Agronomist Photographic illustrations by Dwight Kimsey" BOTH NATIVE and introduced wheatgrasses (species of the genus Agropy- rOil) rate high in importance in Wyoming. The native species are often both abundant and widespread. They are persistent, drought-resistant, and, even if not always palatable, at least high in nutritive value. one of the in- troduced species is a serious pest; many have specialized uses for which they are better suited than the indigenous vegetation. Two previous Wyoming Agricultural Experiment tation bulletins have borne the title "Wheatgras es of Wyoming". The first, publi hed in 1903, reported that "the wheatgrasses are the most nutritious hay and pasture grasses we have" and covered seven native specie. The second, published in 1952, treated 17 species, 10 native and 7 Old World introductions. In thi third edition no new natives have been discovered, but for Wyoming the promise of new introductions of value, coming from both the ew World and the Old, is bright. The mo t promising Old World newcomer is amur wheatgra , Agropy- ron amurense, although this species needs more testing and is rarely available commercially. The annual report for the calendar year 1949 of the Rocky Mountain Forest and Range Experiment Station reports that this plant ap- pears "to have considerable merit" for eeding "in depleted parks in the aspen and spruce-fir zone (8,500 to 10,000 it. elevation)." mur wheat- gras has hown promise in test plantings at both heridan and Laramie. Most promising of the ew World wheatgra es now on trial is the Argentine Agropyron scabriglume. In addition to the e sources of material the 11 western states have recently (April 1955) voted Agropyron the genus most likely to yield results from domestic exploration. AGROPYRON AND THE HORDEAE In the generally accepted family tree of the grasse, Agropyron as a genu falls into the tribe Hordeae, a distinctive group of clo ely related (a indicated by their crossability) and valuable cereal and forage crops. Here Agropyron bridges completely the <Yapbetween the primitive, rhizomatou perennials of Elymus and the advanced, large. grained annuals of Triticum. Witllin Agropyron are closel related groups, sometime given ectional standing and sometime made into genera. Chief among the e group are the annuals, two type of tufted perennial (Eu-Agropyron and Roegneria), and the rhizomatou pecies of the ection Holopyron. $Research assistanl in Range fanagemenl. -2- As more is known about the Hordeae, older divi ions seem more and more artificial ; Agropyron itself may be known in the future in a form greatly modified from that we recognize today. Research in this tribe is progressing more rapidly than in any other group of grasses. The reticulate pattern of evolution will be unravelled slowly but already it is pos ible to visualize the over-all pattern of progression from rhizornatou types to tufted perennials to annuals. Agropyron dasystachyum Agropyron trachycaulum var, unilaterale DISTRffiUTIO OF THE ATIVE WHEATGRASSES Agropyron spicatum, the typical form of Agropyron trachycaulum, and Agropyron smithii are known throughout Wyoming. One has only to eek the proper habitat to find them. Three well-known Wyoming wheatgra e of more re tricted range are illu trated here, namely Agropyron scribneri, Agropyron dasystachyum, and Agropyron trachycaulum var. unilaterale. AGROPYRO Gaertn. The Wheatgras es Our spiked perennial . ligule eldom over 1 mm, long, mernbranaceou ; pikelet ingle at the nodes of the rachi ; about half and half tufted and rh izomatous; al 0 about half and half with flat blade and blades involute; variably 3- to many· flowered; spikelet about half and half awned and un· awned; glume 2; lemma firm, everal-nerved ; palea prominent, 2-keeled, stamens 3; the short, di tinct tyle with two plumo e stigmas. -3- As a genus, ubiquitous, ranging from the alpine zone to the river bottoms, in woods and on open slopes, and in all soil types, occurring around the world and divisible into more than one hundred specific units. KEY TO THE SPECIES Plants with long, creeping rhizome (Sect. Holopyron and Sect. Elytrigia) Lemmas pubescent Lemma awned Lemma awn long, trongly divergent 1. Typical A. albicans Lemma awn hort, straight or absent Lemma awnless, hirsute 2. A. trichophorum. Lemma with short awn, puberulent 3. A. smithii var. molle Lemma awnles Plants glaucous, glumes large, spikelets many- flowered 3. A. smithii var. molle Plants not glaucou , glumes small, spikelets few-flowered 4. A. dasystachyurn Lemmas glabrous Lemmas awned, the awn trongly divergent 1. A. albicans var. grifJithsii Lemma awns, if present, short and traight Plant u ually trongly glaucous, leaves 2·4 mm. wide, the margin often somewhat curled Glumes 5·6 mrn. long, pikelet distant, plant not glaucous 5. A. riparium Glume 8·12 mm. long, spikelets imbricate, plant very glaucous 3. Typical A. smithii Plant not glaucou , leaves 5·10 mrn, broad, flat Glume tapered, short-awned 6. A. repens Glumes oblong, truncate 7. A. intermedium Plants essentially cae pitose, the innovations at most very hortly toloniferous pikelets appressed to axi of the pike ( ect. Roegneria) Plant alpine; lemma pubescent 8. A. trachycaulum. var. latiglume Lemma not pubescent (rarely scabrou ) Awn on lemma traight or ab ent Awns if present, hort, at most Yz length of lemma All spikelets on same side distant Glumes % or less length of spikelet; leaves trongly involute; dry, sterile open ground 9. A. spicatum f. inerme Glumes about equaling the spikelet; leaves mostly flat Florets 1-3. moist treambanks or woods 8. Typical A. trochy cauluni Florets 5-11, cultivated in field 10. A_ elongaium. At lea t the upper spikelets strong imbricate 8. A. trachycaulwn val'. majus Awns long, a long as or longer than the lemma 8. A. traclvycauluni val'. unilaterale Awns on lemma present and divergent Glume awnless or awn pointed pikelets imbricate, blades 3-8 mm. broad 8. A. trachvcauluni val'. andinum Spikelets di tant, blade 2-3 mm. broad 9. A. spicatum Glumes long-awned Culm prostrate spreading, alpine 11. A. scribneri Culm erect, rocky lope and plain at low elevations 12. A. saxicola and A. saundersii pikelets strongly reflexed from the axi of the pike ( ect. Eu- gropyron) Glumes twisted, the margin very narrow, wide-headed 13. A. cristatuni Glumes traight, the hyaline margin broad and con picuou narrow headed 14. A. desertorum. 1. Agropyron albicans cribn. & mith. Montana Wheatgras Perennial with creeping rhizome, the erect culm up to 8 dm. tall, whitish; blade 1-2 mm. broad, 1-2 dm. long, rather involute, both sheath and blade u ually scabrous; spike 7-10 em. long, the spikelet di tant, 3- to 7-flowered; lemma 8-12 mrn. long tapering to a divergent awn 1-2 em. long, pube cent. (Plate II, Fig. 1.) Plains and dry lope, outh Dakota to Iberta and Colorado. -5- Plate I. The Annual Wheatgrasses FIG. l-Agropyron triticeum or Ere- FIG. 2-Agropyron orientale or Ere- mopyrum triticeum, the only one of mopyrum orientale, which has been the group occurring spontaneously reported introduced into the Mon- in Wyoming. tana flora. FIG. 3--Agropyron buonapartis or FIG. Agropyron buonapartis var. Erernopyrum buonapartis, which is pilo urn or Eremopyrum buona- now under observation at the Wyo- partis var, pilosum (E. hirsutum), ming Experiment Station. a very hi pid form. -6- lao Agropyron albicans var. griffithsii (Scribn. & mith ) Beetle Griffiths Wheatgrass Differing from typical A. albicans only in having glabrous lemmas and broader (up to 3.5 rnm.] leaf blades. (Plate If, Fig. 2.) North Dakota, South Dakota, Wyoming, and Colorado. Both A. albicans and its variety are indicators of sagebrush ranges in the highest condition class. 2. Agropyron trichoph orum. (Link) Richt. Stiffha ir Wheatgrass Perennial; culms 6·10 drn. tall, glabrou blades flat, 3-7 mm. wide; sheaths of the lower leaves hirsute; spikes 10-20 cm. long; rachis more or less hirsute; spikelets den ely hirsute, awnless, 1-2 em. long, 4- to 7.flowered; glumes several-nerved, acutish, hirsute 2.5-1 ern. long, 5- to 7-nerved; lemma hirsute with long white hairs on the upper surface and margin ; palea slightly shorter than the lemma, long-ciliate on the keels. (Plate Ill, Fig. 4.) Sparingly planted in Wyoming; native of Russia; on pasture in the spring and early summer well eaten by cattle and horses, not so well by sheep. The hay is coarse but well liked by cattle. Experiences with thi grass have been di appointing in Wyoming. In general it may be said that it produces uneven stand. It can only be rec- ommended for the same situations under which intermediate wheatgra s may be expected to give superior performance. Plate II FIG. I-Typical Agropyron albicans; FIG. 2-A. albicans var. griftithsii, dif- note the unawned pair of glumes fering in lacking strongly pubes- at the top. cent glume and lemmas. -7- 3. Agropyron smithii Hydb, Wyoming Wheatgrass (Western Wheatgrass, Bluestem Wheatgrass) mooth perennial with strong, extensively creeping rhizomes; culms erect. up to 8 dm. tall, very glaucous; leaf blades conspicuously ribbed dor- sally, stiff, 2.6 mm. broad, 5-12 ern, long, flat or involute, sharply scabrous, sheaths, stems and leaves very glaucous (bluish-green); spike 7-15 em. long, the spikelets imbricate, often somewhat divergent; spikelets 1-2 ern. long, 6- to 10-Aowered; first glume 8·10 rnrn. long; second glume 10-12 mm. long, both glumes rigid, gradually tapering from near the base into a short awn; lemmas 8-12 rnm. long, glabrous or pubescent near base, obscurely nerved, often mucronate or awn-tipped. (Plate III, Fig 1.) Mostly on alkaline soil below 7,500 ft.