138 



CHENOPODIACE^E. 



Obione. 



5. OBTONE. Geert. fruct. 2. p. 198. t. 126. /. 5 ; Moq.-Tand. Chenop. p. 78. OBIONE. 



[ Etymology uncertain.] 



Flowers moncecious or dioecious. Sterile fl. without bracts. Calyx 4 - 5-sepalled. Stamens 

 4-5. Fertile with two bracts at the base, more or less united below, at length inflexed, 

 indurated or corky, connivent. Calyx none. Styles 2, united below. Fruit compressed, 

 covered with the bracts, muricate or naked : utricle membranaceous. Seed vertical, ovate, 

 with a short beak ; the integument double. Embryo completely annular. — Herbs or 

 undershrubs. Leaves elliptical or more or less ovate. Flowers crowded in small glomerules. 



1. Obione arenaria, Moq.-Tand. Seabeach Orach. 



Stem herbaceous, diffuse ; leaves alternate, nearly sessile, oblong-ovate, silvery-mealy 

 underneath, very entire , upper ones acute or acuminate ; bracts of the fruit united below, 

 cuneate, retuse, toothed on the margin and muricate on the sides. — Moq.-Tand. Chenop. 

 p. 71. Atriplex arenaria, Nutt. gen. 1. p. 198 ; Torr. fl. 1. p. 293 ; Beck, hot. p. 297. 



Annual. The whole plant covered with a silvery mealiness. Stem spreading ; the branches 

 a foot or more in length, assurgent or procumbent. Leaves 1-2 inches long, rather pale 

 green above ; the lower ones very obtuse, or sometimes retuse. Perfect flowers mostly in 

 terminal glomerate spikes. Fertile flowers crowded and axillary. Bracts of the fruit broad 

 and closely applied to each other, 2 - 3-toothed on each side. Seed lenticular. 



On the seabeach of Long Island. August - September. 



6. ACNIDA. Linn.; Moq.-Tand. Chenop. p. 78. COMMON WATER-HEMP. 



[ From the Greek, a, without, and knide, a nettle ; because it resembles a nettle, but does not sting.] 



Flowers dioecious, without bracts. Sepals membranaceous. Sterile fl. Calyx of five 

 somewhat equal sepals. Stamens 5, very short, inserted into the receptacle. Fertile fl. 

 Calyx of three unequal sepals. Ovary 3 - 5-angled : stigmas 3-5, linear, spreading. 

 Achenium 3 - 5-angled. Seed vertical, compressed, with a double integument. Embryo 

 nearly annular. — Annual, smooth herbs, growing in swamps, with alternate lanceolate entire 

 leaves, and the flowers in axillary and terminal racemes, which are more or less paniculate. 

 The apparent bracts in this genus are abortive or undeveloped flowers. 



1. Acnida cannabina, Linn. Common Water-hemp. 



Fruit acute-angled, smooth. — Linn. sp. 2. p. 1027 ; Michx. fl. 2. p. 234 ; Pursh, fl. 1. 

 p. 208 ; Ell. sk. 2. p. 694 ; Bigel. fl. Bost. p. 367 ; Torr. compend. p. 373 ; Beck, hot. 

 p. 297 ; Moq.-Tand. Chenop. p. 79. 



