2(1). Mature achenes included in the perianth; leaves usually much more than 

 1 cm. wide; distribution widespread var. hydropiperoides. 



2. Mature achenes slightly exserted from perianth; leaves rarely more than 1 cm. 



wide; distribution mostly on the Gulf Coastal Plain 



var. opelousanum. 



Var. setaceum (Baldw.) Gl. [P. setaceum Baldw., Persicaria setacea (Baldw.) 

 Small]. Fig. 415. 



Var. hydropiperoides [Persicaria hydropiperoides (Michx.) Small]. Fig. 416. 



Var. opelousanum (Ridd.) Stone [P. opelousanum Ridd., Persicaria hydro- 

 piperoides var. opelousana (Ridd.) J. S. Wils.] Fig. 417. 



Fam. 52. Chenopodiaceae Vent. Goosefoot Family 



Herbaceous weedy plants, glabrous or pubescent, with inconspicuous flowers; 

 stems more or less succulent, often articulate; leaves opposite or alternate with 

 no stipules nor scarious bracts, sessile or petiolate; blades flat, broad or often 

 succulent and cylindrical or subterete, sometimes reduced to scales, entire, dentate 

 or lobed; flowers perfect, unisexual or polygamous, usually regular, minute, 

 usually green, with the free perianth imbricated in the bud, usually solitary in 

 small cymose glomerules that are spicate, axillary, paniculate or cymose, or 

 flowers axillary and solitary, sometimes arranged in terminal strobiles or sunken 

 in depressions in the stem; stamens as many as lobes of the flower or occasionally 

 fewer and inserted opposite them or on their bases; ovary superior, l-locular, 

 becoming a 1 -seeded thin utricle or rarely an achene; styles or stigmas 2, rarely 

 3 to 5; perianth simple, persistent, mostly enclosing the fruit; embryo coiled 

 into a ring around the mealy endosperm (if any is present) or conduplicate or 

 spiraled. 



About 100 genera and 1,400 species, world-wide, many weeds. 



Similarly to the amaranths, most of our chenopods are found in weedy areas, 

 commonly called "wastelands," the reasons being mainly because they are often 

 poorly drained, subject to flooding and are often saline or alkaline soils. Because 

 of this, it is very possible that we should have included more of these species. 

 However, since we have based our treatment on factual evidence instead of on 

 speculation it must stand as is. 



1. Stems jointed; leaves reduced to small alternate or opposite scales; flowers 

 sessile, borne in the depressions of the joints of fleshy spikes or 

 along the stem (2) 



1. Stems not joined; leaves not scalelike but sometimes linear (3) 



2(1). Branches and leaves opposite; seed pubescent; embryo conduplicate; endo- 

 sperm lacking 1. Salicornia 



2. Branches and leaves alternate; seed smooth; embryo partially annular, sur- 



rounding an abundant endosperm 2. Allenrolfea 



3(1). Bracts and leaves strongly spinulose at the tips; flowers perfect; fruiting 

 perianth segments broadly winged transversely 3. Salsola 



3. Bracts and leaves not spinulose, the spines (if present) cauline in origin; 



fruiting perianth segments usually not transversely winged, if so 

 the flowers in part imperfect (4) 



4(3). Leaves opposite; perianth segments strongly overlapping; plants rhizomatous 

 4. Nitrophila 



4. Leaves all or mainly alternate; perianth segments rarely overlapping; plants 



very rarely rhizomatous (5) 



834 



