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|Family: Amaranthaceae||View Description||Dichotomous Key|
|Genus: Amaranthus||View Description||Dichotomous Key|
|Species:||View Description||Dichotomous Key|
Amaranthus spinosus L.
Habit: Monoecious. Stem: erect, 2--10(20) dm, simple to many-branched, glabrous or sparsely hairy distally; each node with paired, divergent spines 0.8--1.5(2.5) cm. Leaf: petiole 4--9 cm; blade 20--10(15) cm, 1.5--5 cm wide, +- ovate, base wedge-shaped, tip acute or +- obtuse, margins flat or +- wavy. Inflorescence: axillary, generally of pistillate head-like clusters, and terminal of pistillate clusters and some terminal staminate +- flexible axes, 4--8 cm, 0.4--0.8 cm wide (including flowers), green to silver-green; bracts < perianth parts, spine-like, lanceolate to lance-ovate. Flower: staminate perianth parts 5, 1.5--2 mm, stamens 5; pistillate perianth parts 5, 1.5--2 mm, oblanceolate to spoon-shaped, tip obtuse to spined; stigmas 3, erect to spreading. Fruit: irregular-dehiscent or indehiscent; 1.5--2.2 mm, +- spheric to ovoid. Seed: 0.8--1 mm, lenticular, round, dark brown to black, smooth, shiny. Chromosomes: 2n=34.
Ecology: +- rare waif; roadsides, disturbed areas; Elevation: < 700 m. Bioregional Distribution: SCo, w DMoj; Distribution Outside California: to eastern United States; +- cosmopolitan; native to tropical America. Flowering Time: Jun--Oct
eFlora Treatment Author: Mihai Costea
Jepson Online Interchange
Previous taxon: Amaranthus retroflexus
Next taxon: Amaranthus torreyi
Citation for this treatment: Mihai Costea 2017. Amaranthus spinosus, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=12945, accessed on February 21, 2017.
Citation for the whole project: Jepson Flora Project (eds.) 2017. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on February 21, 2017.