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Go to last lab (Orchids) Go to lab syllabus
Introduction: This last lab comprises the majority of the graminoids. The term 'graminoids' refers to the monocot life form that entails narrow, ribbon-shaped (or finer) leaves and generally inconspicuous, predominantly wind-pollinated flowers. All in this order are relatively closely related. They can be difficult to tell apart, especially those in the first three families. Familiarize yourself with all bold-faced terms.
Poaceae, the grass family ( = Gramineae)
Diagnostic family characteristics:
- Leaves flat or involute, 2-ranked.
- Leaf sheaths generally open, with a ligule that is loose from the leaf blade.
- Flowers bisexual and arranged in a characteristic inflorescence referred to as a spikelet, composed of two outer glumes subtending one or more florets. Each floret comprises two bracts, an outer lemma and an inner palea.
- Fruit is a grain, or karyopsis.The grasses are one the world's largest and best studied families of angiosperms. Important as forage and human food, even used in construction (bamboo), the grasses are perhaps the fittingest family with which to cap off our Vascular Flora of Wisconsin experience!
Key out species 171: Avena sativa 'oats' [Tribe Aveneae]
Voss notes that "the awns on the lemmas of many species in this tribe are very distinctive in being tightly twisted or coiled, and often darker in color, on the lower portion." Spikelets in the Aveneae are pedicelled, containing 2 or more perfect florets (sometimes with additional staminate or sterile florets present above the fertile one), and with glumes longer than the lowest floret, appearing to +/- enclose the florets in many genera.
172. Elymus canadensis 'Canada wild rye'
Canada wild rye is a short-lived, cool-season, perennial, native grass. The stout, hollow, tufted culms range from 2.5 to 6.6 feet tall. It is able to reproduce by both seed and vegetative means but rapid seedling establishment is its primary mode of reproduction. Therefore, it is favored by disturbance. It is typically associated with mesic environments; typical sites include streambanks, lakeshores, floodplains, prairies and fields.
173. Eragrostis cilianensis 'Love grass,' 'Stink grass'
This small, annual, introduced grass commonly occurs commonly on shallow, disturbed sites. It is low growing and has ovate shaped inflorescenses with ascending branches. The genus is extremely distinctive when flowers / fruits are present: spikelets are many-flowered and strongly compressed laterally.
Cyperaceae, the sedge family
Diagnostic family characteristics:
- Leaves flat, involute, or obsolete, 3-ranked.
- Leaf sheaths closed, often with a ligule that is adnate to the leaf blade. Sides of the sheath are referred to as the ventral sheath and the dorsal sheath (front and back respectively).
- Flowers unisexual or bisexual, each subtended by a single bract. In the genus Carex, a perigynium completely encloses the female flower and serves as the dispersal unit.
- Fruit an achene.One of the world's largest genera is in this family, the genus Carex, with roughly 2,000 species worldwide. It is traditionally divided into three or four subgenera, two of which occur in Wisconsin:
subgenus Vignea
subgenus Carex
Stigmas
2
3 (2 in a few sections)
Spikelets
bisexual, all alike, sessile
unisexual or predominantly so, rarely sessile
Achenes
lenticular
triangular or terete in cross section
(lenticular in a few sections)
You can learn Carex in Wisconsin using Andrew Hipp’s (a former TA of this course) Field Guide to Wisconsin Sedges. Other good books for learning Cyperaceae are Gray's Manual of Botany, 8th edition (1950), and Voss's Michigan Flora, Vol. I.Key out species 174: Carex lacustris 'Lake sedge'. Subgenus Carex.
175. Schoenoplectus tabernaemontani 'Soft-stem bulrush' (= Scirpus validus)
This sedge grows up to 2 meters with stems up to 1 cm in diameter. It spreads via rhizomes and grows in both fresh and brackish water. Defined broadly, the species is widespread worldwide. Keep in mind that plants commonly called 'bulrushes' are sedges (Cyperaceae) and not rushes (Juncaceae). Generic and specific circumscription is in flux in this genus. This species can be very difficult to distinguish from the hard-stem bulrush, S. acutus. The two are said to hybridize readily and may frequently grow near one another.
Juncaceae, the rush family
Diagnostic family characteristics:
- Leaves flat, involute, or terete. Terete leaves may be hollow or septate, i.e. with crosswalls.
- Leaf sheaths open, sometimes hairy in one of our genera.
- Flowers bisexual, each subtended by six tepals in an actinomorphic arrangement.
- Fruit a capsule filled with many tiny seeds. Seeds may or may not have a slender appendage, often referred to as a tail, at the end.Key out species 176: Juncus tenuis 'path rush'
Key out species 177: Luzula multiflora 'wood rush'
Genera to learn:
178. Sparganium 'common bur-reed' (Sparganiaceae)
This emergent aquatic plants has a somewhat thick zigzag inflorescence axis with a few spherical heads of flowers. The heads are green in early season, becoming brown and bur-like later. The fruits are achenes with beaks. It blooms May to August and is found throught the state.
179. Typha 'Cattail' (Typhaceae)
This tall perennial herb is characterized by a creeping rootstock; long, flat leaves; flowers in a dense cylindrical terminal spikes; and brown, cylindrical fruits with a velvety surface. They grow in freshwater swamps in both temperate and tropical regions. Native Americans had numerous uses for cattails, they made a type of flour out of the roots and made numerous things from baskets to wigwams out of the leaves. In WI the only species are: Typha latifolia (wide leaves), Typha angustifolia (narrow leaves), and a hybrid between the two, Typha X glauca.
180. Xyris 'Yellow-eyed grass' (Xyridaceae)
Different species of this perennial range from endangered to invasive. It can form large colonies in wet, sandy lakeshores. Our two species are both fairly short plants of low-nutrient wetlands. The inflorescence is distinctive: many imbricated bracts, each subtending a flower and together forming a cone-like spike. Tufted stems of some species grow up to 3 feet tall. The three-petalled flowers have rounded yellow petals and unfold in the morning, remaining open only a few hours. The seeds are tiny and shiny.