OregonFlora: Miscanthus sinensis vs. Poaceae

	Miscanthus sinensis	Poaceae
		grass family
Habit		Plants annual or perennial; cespitose, rhizomatous or stoloniferous.
Culms		usually herbaceous; erect to sprawling; internodes hollow or solid; nodes prominent and usually swollen.
Leaves		alternate, 2-ranked; each consisting of a sheath that encircles the culm and a blade; sheaths open or closed with margins fused for much or all of their lengths; auricles present or absent; ligules usually present at the sheath-blade junction; on the side toward the culm, membranous or of hairs, rarely absent; blades usually linear to lanceolate with parallel veins.
Inflorescences		usually complex aggregations of spikelets into panicles; racemes, or spikes, usually with a main axis; spikelets usually supported on pedicels; disarticulation above or below the glumes, usually beneath each floret, sometimes in or below the inflorescence axis.
Spikelets		consisting of 2 glumes subtending 1–many florets arranged on either side of the rachilla, laterally or dorsiventrally compressed, occasionally round in cross section.
Glumes		(0)2, with an odd number of veins, sometimes awned.
Stamens		(0)3(6).
Florets		usually bisexual, sometimes pistillate, staminate or sterile, usually consisting of a lemma and palea with the flower between them; the flower itself reduced to stamens; a pistil; and 2 lodicules.
Fruits		usually a caryopsis.
Lemmas		usually with an odd number of veins, awned or awnless, with calluses; lemma awns; if present, arising at the tip; along the back or near the base, sometimes curved; bent, or twisted.
Paleas		usually 2-keeled, often with additional veins.

	Miscanthus sinensis	Poaceae
Distribution	[WildflowerSearch map] [BONAP county map]	[BONAP county map]
Discussion		Cosmopolitan. Approximately 700 genera; 99 genera treated in Flora. With approximately 11,000 species, Poaceae is the fourth largest plant family in the world and the most economically and ecologically important. Grasses grow in most terrestrial habitats and are dominant or co-dominant in grasslands and savannas. The world’s major grain crops are grasses, including corn, rice, wheat, barley, sorghum, millet, oats, and rye. Some grass species are serious weeds, threatening natural ecosystems, harming livestock, and competing with cultivated crops. Arundo donax, giant reed, has spread very locally from ornamental plantings in Jackson County. Plants are strongly rhizomatous; culms (2)3–10m tall, 2+cm wide near the base; leaves 30–100 × 2–7(9)cm; inflorescence a fluffy panicle; lemmas 8–12 mm with hairs 4–9 mm. Efforts are being made to eradicate this population. It is an invasive weed in California. The following identification hints may be helpful when keying within this family: If the inflorescence is a dense spike, break the inflorescence axis to isolate a node and count the spikelets attached there. Spikelet and lemma measurements exclude the awns. To determine spikelet compression, break off a single spikelet and lay it down. If both glumes are visible at the same time, it is laterally compressed. If only one glume is visible, it is dorsiventrally compressed.
Source		Flora of Oregon, volume 1, page 331
Web links	Local floras: BC, OR, WA Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: OR Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Miscanthus sinensis

Poaceae

grass family

Habit

Plants annual or perennial; cespitose, rhizomatous or stoloniferous.

Culms

usually herbaceous; erect to sprawling;

internodes hollow or solid;

nodes prominent and usually swollen.

Leaves

alternate, 2-ranked; each consisting of a sheath that encircles the culm and a blade;

sheaths open or closed with margins fused for much or all of their lengths;

auricles present or absent;

ligules usually present at the sheath-blade junction; on the side toward the culm, membranous or of hairs, rarely absent;

blades usually linear to lanceolate with parallel veins.

Inflorescences

usually complex aggregations of spikelets into panicles; racemes, or spikes, usually with a main axis;

spikelets usually supported on pedicels;

disarticulation above or below the glumes, usually beneath each floret, sometimes in or below the inflorescence axis.

Spikelets

consisting of 2 glumes subtending 1–many florets arranged on either side of the rachilla, laterally or dorsiventrally compressed, occasionally round in cross section.

Glumes

(0)2, with an odd number of veins, sometimes awned.

Stamens

(0)3(6).

Florets

usually bisexual, sometimes pistillate, staminate or sterile, usually consisting of a lemma and palea with the flower between them; the flower itself reduced to stamens; a pistil; and 2 lodicules.

Fruits

usually a caryopsis.

Lemmas

usually with an odd number of veins, awned or awnless, with calluses;

lemma awns; if present, arising at the tip; along the back or near the base, sometimes curved; bent, or twisted.

Paleas

usually 2-keeled, often with additional veins.

Miscanthus sinensis

Poaceae

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Cosmopolitan. Approximately 700 genera; 99 genera treated in Flora.

With approximately 11,000 species, Poaceae is the fourth largest plant family in the world and the most economically and ecologically important. Grasses grow in most terrestrial habitats and are dominant or co-dominant in grasslands and savannas. The world’s major grain crops are grasses, including corn, rice, wheat, barley, sorghum, millet, oats, and rye. Some grass species are serious weeds, threatening natural ecosystems, harming livestock, and competing with cultivated crops. Arundo donax, giant reed, has spread very locally from ornamental plantings in Jackson County. Plants are strongly rhizomatous; culms (2)3–10m tall, 2+cm wide near the base; leaves 30–100 × 2–7(9)cm; inflorescence a fluffy panicle; lemmas 8–12 mm with hairs 4–9 mm. Efforts are being made to eradicate this population. It is an invasive weed in California. The following identification hints may be helpful when keying within this family: If the inflorescence is a dense spike, break the inflorescence axis to isolate a node and count the spikelets attached there. Spikelet and lemma measurements exclude the awns. To determine spikelet compression, break off a single spikelet and lay it down. If both glumes are visible at the same time, it is laterally compressed. If only one glume is visible, it is dorsiventrally compressed.

Source

Flora of Oregon, volume 1, page 331

Web links