Spartina ×caespitosa

A. A. Eaton
Common names: Mixed cordgrass
Treatment appears in FNA Volume 25. Treatment on page 249.

Plants rhizomatous or not; rhizomes, when present, thick, usually purplish-brown, scales closely imbricate. Culms to 120 cm tall, 1-3 mm thick, indurate, solitary or in small, dense clumps. Sheaths mostly glabrous, throats glabrous or short-pilose; ligules 0.5-1 mm; blades 8-56 cm long, 2-6 (7) mm wide, usually involute, abaxial surfaces glabrous, adaxial surfaces glabrous or scabrous, margins strongly scabrous, blade of the second leaf below the panicles 8-56 cm long, 2-5 (7) mm wide. Panicles 9-20 cm, not smoothly cylindrical, with 3-9 branches; branches 3-9 cm, appressed or spreading, with 20-50 spikelets. Spikelets 10-17 mm, lanceolate to ovatelanceolate. Glumes glabrous or sparsely hispidulous, keels glabrous, hispid in whole or in part, or ciliate; lower glumes 4-9 mm, acuminate or awned; upper glumes 10-17 mm, exceeding the florets, keels hispid, lateral-veins prominent, 1 on each side of the keel or 2-3 on 1 side of the keel, apices acuminate or awned; lemmas glabrous or sparsely hispidulous, apices obtuse, rounded, obscurely lobed, or apiculate; anthers 3-6 mm, poorly filled, indehiscent. 2n = 60, 60+2.

Distribution

Maine, Md., N.J., Mass., N.B., N.S., P.E.I., Va., Conn., N.Y., Del., N.H., R.I.

Discussion

Spartina ×caespitosa is found in disturbed areas of the drier portions of salt and brackish marshes, at some distance above the intertidal zone. It occurs sporadically along the coast from Maine to Maryland, a region where its putative parents, S. pectinata and S. patens, are sympatric. None of the populations Mobberley (1956) examined was growing in undisturbed land.

Mobberley's (1956) investigations led him to conclude that the populations of S. ×caespitosa are polythetic in origin. Part of the evidence for his conclusion was the variability he observed. It is this variability that makes it necessary to bring out the hybrid at several locations in the key. Its distribution is, however, very limited, a fact that may be more useful for identification than any of the morphological characteristics examined.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number."thick" is not a number.

... more about "Spartina ×caespitosa"
indehiscent +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
apiculate +, lobed +, rounded +, obtuse +, awned +  and acuminate +
Mary E. Barkworth +
A. A. Eaton +
1 (?) +  and 3 (?) +
multiple +, , +  and single +
keeled +  and rounded +
rhizomatous +
not fused +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
not pseudopetiolate +
8 cm80 mm <br />0.08 m <br /> (56 cm560 mm <br />0.56 m <br />) +
pubescent +  and glabrous +
involute +  and flat +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
divergent +, whorled +, opposite +, alternate +  and arranged +
spreading;appressed +
spikelike +
3 cm30 mm <br />0.03 m <br /> (9 cm90 mm <br />0.09 m <br />) +
triangular +  and dome--shaped +
membranous +
Mixed cordgrass +
in small , dense clumps +  and solitary +
0 cm0 mm <br />0 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
10 cm100 mm <br />0.1 m <br /> (350 cm3,500 mm <br />3.5 m <br />) +
indurate +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Maine +, Md. +, N.J. +, Mass. +, N.B. +, N.S. +, P.E.I. +, Va. +, Conn. +, N.Y. +, Del. +, N.H. +  and R.I. +
not waisted +
capillary +
pistillate +  and staminate +
sometimes longer +
bisexual +  and fertile +
round +  and compressed +
reduced +
shorter or longer +
subtending +
hispidulous +  and glabrous +
unequal +
uncinate +
paniculate +  and racemose +
3 cm30 mm <br />0.03 m <br /> (70 cm700 mm <br />0.7 m <br />) +
hollow +  and solid +
hispid +  and glabrous +
not absent +
hispidulous +  and glabrous +
sometimes longer +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
membranous +
inconspicuous +
awned +  and acuminate +
0.4 cm4 mm <br />0.004 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
concealed +  and prominent +
2 +  and 1 +
8cm +  and 56cm +
cylindrical +
9 cm90 mm <br />0.09 m <br /> (20 cm200 mm <br />0.2 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
dry +  and fleshy +
spikelike +
elongate +
purplish-brown +
2 +  and 3 +
usually divergent +  and strongly divergent +
20 +  and 50 +
lanceolate +  and ovatelanceolate +
1 cm10 mm <br />0.01 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
1 +  and 3 +
compound +  and simple +
2 (?) +  and 3 (?) +
plumose +
Gramineae +
Spartina ×caespitosa +
Spartina +
species +
short-pilose +  and glabrous +
membranous +
1 cm10 mm <br />0.01 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
7 (?) +  and 13 (?) +
not +  and rhizomatous +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +