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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.Examine the spikelet of Avena sativa (oats) set up as a demonstration on the front table and find these parts.
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!
171: Dichanthelium 'Panic grass'
This genus of small grasses is easy to recognize but the species are very hard to tell apart. The species bloom in spring and then again in the fall, taking on a very different habit. Most species are found in prairies and are often hairy.
172. Dactylis 'Orchard grass'
This exotic grass is found in all kinds of disturbed habitats and is an early bloomer. The inflorescence often has a small side branch below the “main” cluster of spikelets.173. Phalaris arundinacea 'Reed canary grass'
This grass has both native and non-native strains in the U.S. The non-native strains are highly invasive and have destroyed many acres of wetlands across the state. There are many marshes around Madison that are dominated by this grass. The tawny-colored inflorescences are densely packed and allow for identification, even from far away.
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.Key out species 174: Carex pensylvanica 'common oak sedge', 'Pennsylvania sedge'.
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' (Typhaceae, former 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)
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.
