This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Annual, erect or decumbent, glabrous branching herbs, similar to the dioecious Amaranths, with alternate petioled thin pinnately veined leaves. Flowers small, green, 1-3-bracted, in terminal and axillary, continuous or interrupted spikes, or clustered in the axils. Stami-nate flowers consisting of 5 scarious erect I-nerved mucronate sepals longer than the bracts, and as many stamens; filaments subulate, distinct; anthers 2-celled. Pistillate flowers without a calyx; ovary ovoid or subglobose; stigmas 2-5, papillose or plumose, short or elongated. Utricle fleshy and indehiscent, or membranous and bursting irregularly or circumscissile; seed erect, smooth and shining. [Greek, without nettle.]
About 6 species, natives of eastern North America and the West Indies. Type species: Acnida cannabina L.
Utricle irregularly dehiscent.
Acnida cannabina L. Sp. Pl. 1027. 1753.
A. rusocarpa Michx. Fl. Bor. Am. 2: 234, pl. 50. 1803.
Succulent, stem stout or slender (sometimes 1' in diameter at the base), usually much branched, 1°-10° tall, the branches ascending. Leaves lanceolate, acuminate but generally blunt-pointed and apiculate at the apex, 2'-6' long, 1/4'-1 1/4' wide, narrowed at the base, entire or slightly undulate; petiole usually shorter than the blade; staminate spikes 1'-5' long, usually dense; sepals oblong-lanceolate or ovate-oblong, acute, acuminate or obtusish, cuspidate or mucronate; fertile spikes dense or loose; stigmas slender, papillose-hispid, i" long; utricle fleshy, indehiscent, 3-5-angled, subglobose or obovoid, 1"-2" long when mature, becoming black, much longer than the bracts.
In salt and brackish marshes, and up the rivers to fresh water, New Hampshire to Florida. Water-leaf. July-Aug.
Acnida floridàna S. Wats. Proc. Am. Acad. 10: 376, a more slender plant, of the southern Atlantic coast, with narrower slender-petioled leaves, the flowers in elongated interrupted spikes, and a smaller utricle, may occur in southern Virginia.
5: 165. 1833-37. Acnida tamariscina Wood, Bot. & Fl 289. 1873.
Similar to the preceding species, much branched, erect, the branches usually slender, erect-ascending. Leaves lanceolate or ovate-lanceolate, 2'-6' long, mostly long-acuminate., but sometimes obtuse at the apex and mucronate or cuspidate-tipped, narrowed at the. base, the petioles commonly shorter than the blades; spikes mostly loose or interrupted, often 5' long; sepals lanceolate, subulate-acuminate; stigmas plumose, rather short; utricle membranous, not angled, 1/2"-1" long, cir-cumscissile; bractlets lanceolate, cuspidate.
In swamps, Illinois to South Dakota, Texas and New Mexico. July-Sept.
A. tuberculata Moq. in DC. Prodr. 132: 278. 1849.
A. tamariscina subnuda S. Wats, in A. Gray, Man. Ed. 6, 429. 1890. A. tamariscina concatenata Uline & Bray, Bot. Gaz. 20:
158. 1895. A. tamariscina prostrata Uline & Bray, Bot. Gaz. 20:
Erect ascending or prostrate, sometimes 10° high, the branches flexuous. Leaves lanceolate to rhombic-spatulate, acute or obtuse, 6' long or less; inflorescence spicate, or glomerate in the axils; utricle ovoid, often tubercled. irregularly dehiscent, about 1/2" long.
Swamps and river shores, Quebec to North Dakota, south to Kentucky, Louisiana and Missouri. Consists of several races, differing in size and habit. July-Sept.
Celòsia argéntea L., a tall glabrous herb with white or pink flowers subtended by a bract and bractlets in a long dense spike, having 5 sepals, filaments adnate at the base, and the ovary with several ovules, widely distributed in tropical regions, has been found as a waif in Montgomery County, Pennsylvania.