Spartina Schreb., Gen. Pl. ed. 8[a]. 43. 1789. Type: Spartina cynosuroides (L.) Roth

Saarela, Jeffery M., 2012, Taxonomic synopsis of invasive and native Spartina (Poaceae, Chloridoideae) in the Pacific Northwest (British Columbia, Washington and Oregon), including the first report of Spartina xtownsendii for British Columbia, Canada, PhytoKeys 10, pp. 25-82 : 29

Spartina Schreb., Gen. Pl. ed. 8[a]. 43. 1789. Type: Spartina cynosuroides (L.) Roth

Ponceletia Thouars., Esquisse Fl. Tristan D’Acugna 36. 1808. Type: Ponceletia arundinacea Thouars.

Solenachne Steud. Syn. Pl. Glumac. 1: 12. 1855. Type: Solenachne phalaroides Steud.

Plants perennial, culms cespitose from knotty bases or solitary from conspicuous creeping rhizomes. Leaves cauline; sheaths open; ligules a line of hairs; blades flat to involute. Inflorescences with multiple branches (i.e., spikes) inserted along a main axis, branches usually alternate, appressed to spreading. Spikelets laterally compressed, one-flowered, arranged in two rows along two sides of a more or less triquetrous axis, disarticulating below the glumes. Glumes unequal, strongly keeled; lower glumes 1-veined, shorter than upper glumes and floret; upper glumes 1-6-veined, usually longer than the floret. Lemmas 1-3-veined, keeled, shorter than the paleas. Paleas 2-veined, thin and papery, longer than the lemma. Anthers 3. Styles 2. Caryopses linear. Base chromosome number, x = 10. Named from the Greek spartine, a cord made from Spartium junceum L.(Spanish Broom; Fabaceae), and probably applied to Spartina in reference to its tough leaves ( Hitchcock 1951).

Key to native and introduced species of Spartina in British Columbia, Washington and Oregon

1	Leaf blades distinctly scabrous on their margins; spikelets tightly appressed and strongly overlapping	2
-	Leaf blades glabrous on their margins (occasionally with a few scattered teeth, but teeth never abundant); spikelets weakly appressed and weakly overlapping	5
2	Culms growing in tufts (i.e., cespitose) from hard knotty bases, rhizomes absent, rarely short; branches appressed, usually not readily discernible within an inflorescence, not distinctly one-sided	Spartina densiflora
-	Culms growing from rhizomes; branches appressed, ascending, or spreading, readily discernible within an inflorescence, distinctly one-sided	3
3	Upper glumes distinctly awned, awns 3-8 mm long; blades 5-15 mm wide; ligules 1-3 mm long; branches pedunculate, rarely sessile	Spartina pectinata
-	Upper glumes unawned or short-awned, when present awns to 2 mm long; blades 0.5-8 mm wide; ligules 0.5-1 mm long; branches sessile, rarely pedunculate	4
4	Glume keels ciliate, hairs stiff, 0.5-0.8(-1) mm long; glumes with two inconspicuous lateral veins on one side of the keel; branches appressed to the main axis; most branches 3-6 mm wide; inflorescences 8-25 cm long; spikelets ovate to lanceolate; florets more or less equaling the upper glumes in length	Spartina gracilis
-	Glume keels scabrous, teeth 0.1-0.2 mm long; glumes with two conspicuous lateral veins on one side of the keel; branches appressed, ascending, or spreading from main axis; most branches 2-2.5 mm wide; inflorescences 3-15 cm long; spikelets linear lanceolate to ovate lanceolate; florets shorter than the upper glumes	Spartina patens
5	Spikelets 8-14(-16.5) mm long; branch rachises 0.4-1 mm wide between spikelets; glumes glabrous or weakly pubescent; leaf blades more or less erect, forming an angle 15-18° with the culm	Spartina alterniflora
-	Spikelets 14-25 mm long; branch rachises 1-2.2 mm wide between spikelets; glumes moderately to densely pubescent; leaf blades ascending to spreading, forming an angle 30-60° with the culm	6
6	Spikelets (15-)16.5-25 mm long; anthers 7-10 mm long, usually fully exserted at maturity; pollen fertile; ligules 1-3 mm long; upper glumes 3-6-veined, 13-22 mm long; glumes (weakly) moderately to densely pubescent with hairs 0.1-0.3 mm long, hairs to 0.6 mm long and usually denser proximally; calluses (1.5-)2-4.5 mm long; branches (3-)4-5(-6) mm wide	Spartina anglica
-	Spikelets 14-17.5 mm long; anthers 5-7(-8.5) mm long, not or incompletely exserted at maturity, indehiscent; pollen sterile; ligules 1-1.5 mm long; upper glumes 3-veined, 12.5-16.5 mm long; glumes weakly to moderately pubescent with hairs 0.1-0.2 mm long, occasionally to 0.6 mm long proximally; calluses 0.6-1.5(-2) mm long; branches (2.5-)3-4 mm wide	Spartina xtownsendii