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smallseed sandmat

petty spurge

Habit Herbs, annual, with taproot.
Stems

erect, unbranched or branched, 5–30 cm, glabrous.

Leaves

petiole 1–10 mm;

blade obovate, oblong, or suborbiculate, 5–25 × 4–15 mm, base attenuate or cuneate, margins entire, apex obtuse, surfaces glabrous;

venation pinnate, midvein prominent.

Involucre

cupulate to slightly turbinate, 0.6–1.1 × 0.7–0.9 mm, glabrous;

glands 4, elliptic, 0.2–0.3 × 0.5–0.6 mm;

horns slightly convergent to divergent, 0.4–0.6 mm.

Staminate flowers

10–15.

Pistillate flowers

ovary glabrous;

styles 0.1–0.2 mm, 2-fid.

Capsules

subglobose, 1.3–2 × 1.5–2.2 mm, slightly 3-lobed;

cocci rounded, with 2 low longitudinal wings, smooth, glabrous;

columella 1.1–1.3 mm.

Seeds

whitish or grayish, subovoid, 1–1.6 × 0.6–1 mm, abaxial faces regularly large-pitted (appearing almost alveolate), adaxial faces longitudinally sulcate;

caruncle deciduous, conic, 0.2–0.5 × 0.2–0.7 mm.

Euphorbia

polycarpa is a highly variable species distributed throughout the Baja California peninsula, eastern Sonora, and the arid southwestern United States from southwestern Arizona to southern Nevada and central California.

l

.

c

.

Wheeler

(1941) divided the species into seven varieties, the majority of which occur in Baja California Sur.

He

reported two of these for the United States: var. hirtella and var. polycarpa.

Variety

hirtella, as the name suggests, was applied to hairy plants.

However

, it is here treated as a synonym of var. polycarpa, because variation in pubescence shows no geographic segregation and ranges along a continuum from glabrous or sparsely to densely hairy, and because glabrous and hairy branches can occur on the same individual.

Cyathial

arrangement: terminal pleiochasial branches 3–5, usually 2–8 times 2-branched, 1st branching level rarely 3-furcate;

pleiochasial bracts similar in shape to and slightly larger than distal leaves;

dichasial bracts distinct, ovate to obovate, base obtuse, margins entire, apex obtuse, usually mucronate;

axillary cymose branches 0–3.

Cyathia

peduncle 0.4–1.1 mm.

Euphorbia polycarpa

Euphorbia peplus

Phenology Flowering and fruiting year-round.
Habitat Edges of gardens, weedy flower beds, roadsides, waste places, open ground near forests.
Elevation 0–1500 m. (0–4900 ft.)
Distribution
from FNA
AZ; CA; NV; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AZ; CA; CO; CT; DE; IA; ID; IL; IN; KY; LA; MA; MD; ME; MI; MT; NC; ND; NH; NJ; NM; NV; NY; OH; OR; PA; RI; TN; TX; UT; VA; VT; WA; WI; WV; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK; Europe; w Asia [Introduced in North America; introduced also in Mexico, West Indies, Bermuda, Central America, South America, Africa, Atlantic Islands, Indian Ocean Islands, Pacific Islands, Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 5 (1 in the flora).

Some of the varieties occurring in Mexico are highly divergent and appear to be sufficiently distinct to merit recognition as species. However, within the flora area, Euphorbia polycarpa is relatively uniform, and the only noteworthy variation involves the size of the involucral gland appendages. In the portion of the California Floristic Province occupied by E. polycarpa (Los Angeles, Orange, western Riverside, western San Diego, and Ventura counties) the appendages are conspicuously larger than those of plants throughout the remainder of its range in the southwestern United States (0.4–1.2 versus 0.1–0.3 mm). Large-appendaged plants are also common in Baja California and correspond well with the type collection. The taxonomic significance of this variation is not clear at this time, and the small-appendaged plants may merit segregation as an infraspecific taxon. However, no formal changes are proposed, awaiting a comprehensive review of the species throughout its range.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 12, p. 283. FNA vol. 12, p. 307.
Parent taxa Euphorbiaceae > Euphorbia > sect. Anisophyllum Euphorbiaceae > Euphorbia > subg. Esula
Sibling taxa
E. aaron-rossii, E. abramsiana, E. acuta, E. agraria, E. albomarginata, E. alta, E. angusta, E. antisyphilitica, E. arizonica, E. astyla, E. austrotexana, E. bicolor, E. bifurcata, E. bilobata, E. blodgettii, E. bombensis, E. brachycera, E. capitellata, E. carunculata, E. chaetocalyx, E. chamaesula, E. cinerascens, E. commutata, E. conferta, E. cordifolia, E. corollata, E. crenulata, E. cumulicola, E. cuphosperma, E. curtisii, E. cyathophora, E. cyparissias, E. davidii, E. deltoidea, E. dendroides, E. dentata, E. discoidalis, E. eriantha, E. exigua, E. exserta, E. exstipulata, E. falcata, E. fendleri, E. florida, E. floridana, E. garberi, E. georgiana, E. geyeri, E. glyptosperma, E. golondrina, E. gracillima, E. graminea, E. helioscopia, E. helleri, E. heterophylla, E. hexagona, E. hirta, E. hooveri, E. humistrata, E. hypericifolia, E. hyssopifolia, E. indivisa, E. innocua, E. inundata, E. ipecacuanhae, E. jaegeri, E. jejuna, E. laredana, E. lasiocarpa, E. lata, E. lathyris, E. longicruris, E. lurida, E. macropus, E. maculata, E. marginata, E. meganaesos, E. melanadenia, E. mendezii, E. mercurialina, E. mesembrianthemifolia, E. micromera, E. misera, E. missurica, E. myrsinites, E. nephradenia, E. nutans, E. oblongata, E. ocellata, E. ophthalmica, E. ouachitana, E. parishii, E. parryi, E. pediculifera, E. peplidion, E. peplus, E. perennans, E. pergamena, E. pinetorum, E. platyphyllos, E. platysperma, E. polygonifolia, E. polyphylla, E. porteriana, E. prostrata, E. pubentissima, E. purpurea, E. radians, E. rayturneri, E. revoluta, E. roemeriana, E. rosescens, E. schizoloba, E. serpens, E. serpillifolia, E. serrata, E. serrula, E. setiloba, E. simulans, E. spathulata, E. stictospora, E. strictior, E. telephioides, E. terracina, E. tetrapora, E. texana, E. theriaca, E. thymifolia, E. tithymaloides, E. trachysperma, E. trichotoma, E. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
E. aaron-rossii, E. abramsiana, E. acuta, E. agraria, E. albomarginata, E. alta, E. angusta, E. antisyphilitica, E. arizonica, E. astyla, E. austrotexana, E. bicolor, E. bifurcata, E. bilobata, E. blodgettii, E. bombensis, E. brachycera, E. capitellata, E. carunculata, E. chaetocalyx, E. chamaesula, E. cinerascens, E. commutata, E. conferta, E. cordifolia, E. corollata, E. crenulata, E. cumulicola, E. cuphosperma, E. curtisii, E. cyathophora, E. cyparissias, E. davidii, E. deltoidea, E. dendroides, E. dentata, E. discoidalis, E. eriantha, E. exigua, E. exserta, E. exstipulata, E. falcata, E. fendleri, E. florida, E. floridana, E. garberi, E. georgiana, E. geyeri, E. glyptosperma, E. golondrina, E. gracillima, E. graminea, E. helioscopia, E. helleri, E. heterophylla, E. hexagona, E. hirta, E. hooveri, E. humistrata, E. hypericifolia, E. hyssopifolia, E. indivisa, E. innocua, E. inundata, E. ipecacuanhae, E. jaegeri, E. jejuna, E. laredana, E. lasiocarpa, E. lata, E. lathyris, E. longicruris, E. lurida, E. macropus, E. maculata, E. marginata, E. meganaesos, E. melanadenia, E. mendezii, E. mercurialina, E. mesembrianthemifolia, E. micromera, E. misera, E. missurica, E. myrsinites, E. nephradenia, E. nutans, E. oblongata, E. ocellata, E. ophthalmica, E. ouachitana, E. parishii, E. parryi, E. pediculifera, E. peplidion, E. perennans, E. pergamena, E. pinetorum, E. platyphyllos, E. platysperma, E. polycarpa, E. polygonifolia, E. polyphylla, E. porteriana, E. prostrata, E. pubentissima, E. purpurea, E. radians, E. rayturneri, E. revoluta, E. roemeriana, E. rosescens, E. schizoloba, E. serpens, E. serpillifolia, E. serrata, E. serrula, E. setiloba, E. simulans, E. spathulata, E. stictospora, E. strictior, E. telephioides, E. terracina, E. tetrapora, E. texana, E. theriaca, E. thymifolia, E. tithymaloides, E. trachysperma, E. trichotoma, E. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
Subordinate taxa
E. polycarpa var. polycarpa
Synonyms Chamaesyce polycarpa Esula peplus, Galarhoeus peplus, Tithymalus peplus
Name authority Bentham: Bot. Voy. Sulphur, 50. (1844) Linnaeus: Sp. Pl. 1: 456. (1753)
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