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smallseed sandmat

wedge sandmat

Habit Herbs, perennial, delicate, with woody, thickened taproot, 15 mm diam..
Stems

prostrate, ascending, or erect, often numerous and wiry, less than 0.1 mm diam., 5–20 cm, glabrous, puberulent, canescent, villous, or hirsute, shorter hairs often uncinate and longer hairs straight or irregularly twisted.

Leaves

opposite;

stipules distinct, triangular, sometimes lacerate or ciliate, 0.2–0.3 mm, glabrous or hairy;

petiole 0.3–1 mm, glabrous or hairy;

blade narrowly to broadly deltate, cordate, or reniform, 2–5(–7) × 1–4.5(–5) mm, base asymmetric, cordate to rounded, margins entire, ± revolute, apex obtuse or rounded, surfaces glabrous or hairy;

only midvein conspicuous.

Involucre

turbinate to campanulate, 0.8–1 × 1.1–1.3 mm, glabrous or hairy;

glands 4, green to yellow-green, oblong to subcircular, 0.2–0.4 × 0.4–0.6 mm;

appendages absent or white, forming narrow rim at edge of gland, rarely slightly wider than gland, (0–)0.1(–0.3) × 0.4–0.6 mm, distal margin entire.

Staminate flowers

8–14.

Pistillate flowers

ovary glabrous or hairy, subtended by triangular pad of tissue;

styles spreading, 0.3–0.4 mm, 2-fid 1/2 to nearly entire length.

Capsules

broadly deltoid, 1.2–1.5 × 2–2.2 mm, glabrous or hairy;

columella 0.9–1.3 mm.

Seeds

reddish brown, ovoid, 4-angled in cross section, 0.8–1.2 × 0.5–0.6 mm, obscurely wrinkled.

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.

Cyathia

solitary at distal nodes;

peduncle 0.7–1.5 mm.

Euphorbia polycarpa

Euphorbia deltoidea

Distribution
from FNA
AZ; CA; NV; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
FL
[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.)

Subspecies 4 (4 in the flora).

Euphorbia deltoidea comprises four narrowly endemic subspecies, all of which are endangered due to habitat loss and fragmentation. The subspecies occur in pine rockland habitat that is free of shrubby undergrowth. Periodic fires are required to keep the rockland habitat open. Subspecies serpyllum is restricted to Big Pine Key, Monroe County, whereas the other subspecies are found only in Miami-Dade County.

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

Key
1. Stems erect or ascending.
→ 2
2. Leaves and stems villous, hairs uncinate or irregularly twisted, 0.2–0.5 mm; leaf blades green.
subsp. adhaerens
2. Leaves and stems villous-hirsute, hairs straight and spreading, 0.6–0.7 mm; leaf blades silver-green.
subsp. pinetorum
1. Stems prostrate.
→ 3
3. Leaves and stems glabrous or very sparsely hairy, hairs 0.1–0.2 mm, appressed, uncinate; leaf blades abaxially reddish, adaxially bright green.
subsp. deltoidea
3. Leaves and stems canescent or villous, hairs either less than 0.1 mm or 0.2–0.5 mm, uncinate or irregularly twisted; leaf blades green or silver-green.
→ 4
4. Leaves and stems villous, hairs uncinate or irregularly twisted, 0.2–0.5 mm; leaf blades as long as wide, green.
subsp. adhaerens
4. Leaves and stems canescent, hairs less than 0.1 mm; leaf blades 2 times longer than wide, silver-green.
subsp. serpyllum
Source FNA vol. 12, p. 283. FNA vol. 12, p. 265.
Parent taxa Euphorbiaceae > Euphorbia > sect. Anisophyllum Euphorbiaceae > Euphorbia > sect. Anisophyllum
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. 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. 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
E. deltoidea subsp. adhaerens, E. deltoidea subsp. deltoidea, E. deltoidea subsp. pinetorum, E. deltoidea subsp. serpyllum
Synonyms Chamaesyce polycarpa Chamaesyce deltoidea
Name authority Bentham: Bot. Voy. Sulphur, 50. (1844) Engelmann ex Chapman: Fl. South. U.S. ed. 2, 647. (1883)
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