This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The habitat of this plant is muddy salt marshes, creeks, mudflats, in south and east of England. The plant has the grass habit. It forms small tufts 1/2 to 1/2 ft. high. The rootstock is long, branched, creeping, the rhizomes and stolons wiry. The stems are erect, rigid, and strict (hence stricta), stout, polished, culms with a succession of tight, firm, short sheaths, which (with the exception of the upper) soon throw off the blades. The leaves are jointed to the sheaths, broad, strict, erect, not so long as the spike, rolled lengthwise, smooth, bluish-green above, narrowed to the base, breaking from the sheath. The ligule is short, silky. The panicle is strict, of 2-3 spikelets, the point of the rachis of the spike awl-like, and scarcely projecting, angled, smooth, the point as long as or longer than the upper spikelet. The spikes are usually close, rigid, overtopping the leaves. The spikelets are yellowish-green, erect, 5 1/2-7 in. long when flowering. The empty glumes are acute, the upper with 2 teeth and a stiff awn, silky, with a rough keel. The second glume is 3-nerved, the lateral nerves with membranous tips. The outer glume is hairy. The plant is 1-2 ft. high, flowering between July and September, and is a herbaceous perennial.
This species occurs on mud flats at Southampton Water, South Hants. The habit is the grass habit. The leaves are broadest at the base and continuous with the sheaths, and are equal to or longer than the spikes (6-8), the tip of the rachis wavy, exceeding the spikelets. The spikelets are numerous and loosely pressed together. The outer glume is hairless. The plant is 2-3 ft. high, flowering between July and September, and is a herbaceous perennial. Dr. O. Stapf has recently described it as follows: "Forming large clumps or beds, 2-3 ft. high, rhizomes and stolons soft, culms with a succession of up to 8 or 9 soft and very smooth sheaths, not throwing off the blades, which gradually decay, spikes usually 5-7, suberect, slender, and often slightly flexuous, overtopped by the long-drawn-out blades, spikelets glabrous to the naked eye, 6-7 1/2 in. long, second glume delicately 5-6-nerved keeled to the very tip".
The habitat of this plant is mud flats, and it is rapidly spreading on the south coast, where it covers an area of 6000-8000 ac. It was first discovered by Messrs. H. and J. Groves in 1879 at Hythe, Southampton Water, but was there in 1870. The plant forms large clumps or beds 2-4 ft. high, with soft rhizomes and stolons. The culms have a succession of up to 10 or 12 somewhat soft sheaths, increasing in length upwards, the lowest throwing off the blades. The leaves are broadest at the base, shorter than in the other species, jointed to the sheaths, not so long as the spike. The spikes, 3-5 as a rule, are more or less erect, rigid, extending above the leaves. The spikelets are 4-9, about 8 1/2 lines long, rather spreading, softly downy, the rachis produced beyond the spikelets, wavy. The second glume is 3-6-nerved, with one or two stouter lateral nerves, the keel ending abruptly below the short, membranous tip. The outer glume is slightly downy. The plant is 1 1/2- 4 ft. high, and flowers from July to September, being a herbaceous perennial.