Poaceae – Grass Family
Poaceae is a massive and incredibly important plant family. With 11,337 species, members of the Poaceae are found on every continent except for Antarctica.[1] Including corn, rice, wheat, sugar cane, bamboo, oats, rye, and barley, grasses feed the global population, not to mention use for building materials, alcohol production, and electricity generation. Earth’s non-human animals also convert the sun’s rays into energy when they ingest and digest grasses, or use them for habitat and shelter. members of the Poaceae are also fundamental engineer ecosystems, holding soils together against eroding winds, collecting accreting sediments in salt marshes, or add organic matter back to the Earth when blades die away in winter.
Members of the Poaceae are in no way comparable to the flamboyant monocots found in Orchidaceae or Asparagaceae. But much subtle grace and beauty is found in the colorful hues, texture, and movement of Willamette Valley prairie grasses. So much so that a number of these very same native species are now used by many of the world’s most influential landscape architects. For example, in New York’s High Line Park, the Dutch master plantsman and “New Perennial” movement advocate, Piet Oudolf, utilized a great deal of Deschampsia and Festuca varieties to add habitat complexity and year-round interest to the park.[2] According to Oudolf, these native grasses dictate his design choices, helping his landscapes appear soft and organic rather than controlled by people in the middle of a bustling metropolis.[3] Of course, taking advantage of native Poaceae is not a new trend in American Landscape design. Looking at the work of garden designer Jens Jensen, particularly in collaborations with the architect Frank Lloyd Wright, the two innovators preferred North American prairie grasses over European or Asian forbs in their developments.[4]
Identifying characteristics of the Poaceae can be complex as leaves and flowers come with unique botanical jargon. Leaves are made up of a Blade (maninae), connected to the stem by hairs called a Ligule (which may be fringed, or solid, vary in length, or be absent entirely). Ligules may or may not have small ear-bud shaped nubs known as Auricles. These auricles are found right where leaf blades attach to stems. If one were to gently pull the leaf blade off, or away from, the plant, a Sheath may be present wrapping around the stem, connecting the two plant parts. The very end of the leaf blade might be flat or or “Prow-shaped,” meaning that it is bent upwards similar to the curved front (prow) of a canoe.
Flowers are very small and difficult to observe without a hand lens. Inflorescence arrangement can be arranged in spikes (flowers are sessile, directly connected to the stem) or panicles (small spikelets with stalks connecting the flower to stem). Individual flowers are wind pollinated and unceremoniously lack showy parts as petals can get in the way of wind. Three stamens, a long pistil, and the ovary (which matures into a grain) are surrounded by multiple bracts with unique, Poaceae specific nomenclature (See glossary).
The Willamette Valley is dominated by grasslands. This is true looking at historic vegetation maps full of wetland prairies, upland prairies, and Oak Savannahs, as well in contemporary agricultural use, with local farmers renaming the Willamette Valley the “Grass Seed Capital of the World.”[5] Introduced European turf and grazing grasses are some of the most challenging invasive species across restored and remnant wetland prairie habitats today. Fast growing, tall, and quick to germinate, Tall Fescue (Festuca arundinacea), Italian Rye-grass (Lolium multiflorum), Meadow Foxtail (Alopecurus pratensis), and Kentucky Bluegrass (Poa pratensis)can readily outcompete native forbs in their first few years trying to establish from seed. These exotic grasses take up available up resources in the form of nutrients, light, and space.[6]
Deschampsia cespitosa – Tufted Hairgrass
Species Code: DECE
Growth Habit: Perennial grass with cespitose habit, meaning that plants grow in dense clump rather than along a spreading rhizome.
Leaves: Compact tuft of many slender, bright green, basal leaves 8 to 20 cm long and 1.5 to 4 mm wide.[7] No auricles present. But do have conspicuous, pointed ligules ranging from 3 to 8 mm long.[8]
Flowers: Inflorescence sits atop long, light brown, straw-like stem ranging from 30 to 80 cm tall. Unripe flowers are folded up against the inflorescence stem, appearing like a loose paintbrush tip of feathery, reddish-purple fronds. When dried, mature flowers unfurl and are arranged in open, pyramidal panicles, 7 to 25 cm long. Overtime, these can droop/nod (easily moved by wind) but are often upright. Within the airy panicle, branches are delicate, leading to two florets (flowers) per spikelet.[9]
Fruits: Spikelets have soft hairs along main axis and at the base of lemmas. 3 to 7 mm long glumes are purplish in color when young, developing into a gold color by Fall.[10]
Ecology: FACW, Facultative Wetland species, found in fresh water wet prairies and meadows that are seasonally flooded, salt marshes, and a wide variety of elevations.[11]
Notes: May be confused with Annual hairgrass (Deschampsia danthonioides), Slender hairgrass (Deschampsia elongata), Colonial bentgrass (Agrostis capillaris), and Creeping bentgrass (Agrostis stolonifera).[12] Tufted hairgrass grows quickly and can easily dominate an entire meadow. This characteristic makes it both helpful and challenging in wetland prairie restoration. Its strong root systems stabilize disturbed sites, streambanks, and marshes, holding together soils and outcompeting invasive species. However, this grass can also outgrow important natives and so restoration practitioners try to limit its use. Deschampsia cespitosa is very acid and heavy metal tolerant and so it is also common in brownfield reclamation, alpine and boreal revegetation work, as well as in bio-filtration swales.[13]
Agrostis exerata – Spike Bentgrass 
Aira caryophyllea var. capillaris
Alopecurus geniculatus – water foxtail
Bromus carinatus var. carinatus – California brome
Beckmannia syzigachne – American Slough Grass
Danthonia californica – California Oatgrass
Deschampsia danthoides – Annual Hairgrass
Elymus elymoides ssp. elymoides – Blue Wildrye
Festuca roemeri var. roemeri – Roemer’s Fescue
Hordeum brachyantherum – Meadow Barley
[1] Simpson, M., Plant Systematics 2nd ed. Academic Press, Burlington, MA. 2010.
[2] The Highline Plantlist: < http://assets.thehighline.org/pdf/12_High%20Line%20Plant%20List.pdf>
[3] Inhabitat.com: < http://inhabitat.com/interview-walking-the-high-line-with-its-garden-designer-piet-oudolf/>
[4] Grese, Robert E., Jens Jensen, Maker of Natural Parks and Gardens. The Johns Hopkins University Press, 1992. ISBN 0-8018-4287-5. pp. 50, 100-02, 159-60, 164-65.
[5] Oregon State University: < http://valleyfieldcrops.oregonstate.edu//grass-seed>
[6] Krueger, J., Bois, S., Kaye, T., Steeck, D., Taylor, T., (2014). Practical Guidelines for Wetland Prairie Restoration in the Willamette Valley, Oregon: Field Tested Methods and Techniques. Lane Council of Governments, Institute for Applied Ecology, City of Eugene. 2014.
[7] Guard, J. (1995). Wetland Plants of Oregon and Washington. Lone Pine Publishing, Edmonton, Alberta. 149
[8] Gilkey, H. Handbook of Northwestern Plants, Revised Edition. Oregon State University Press; Corvallis, OR. 2001.
[9] Darris, D. and P. Gonzalves. 2009. USDA Plant Fact Sheets Tufted Hairgrass, Deschampsia cespitosa. USDA NRCS Plant Materials Center, Corvallis, Oregon. < https://plants.usda.gov/factsheet/pdf/fs_dece.pdf>
[10] Pojar, J., Mackinnon, A., Ed. Plants of the Pacific Northwest Coast. Lone Pine Publishing, Vancouver, Canada, 2004.
[11] USDA Plants Database: < https://plants.usda.gov/core/profile?symbol=DECE>
[12] City of Eugene, Seed Collection Maual, Deschampsia cespitosa, , 2009.
[13] Darris, D. and P. Gonzalves. 2009.
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