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four-o'clock, heart-leaf four-o'clock, heart-leaf umbrella-wort, heartleaf umbrellawort four-o'clock, umbrellawort, wild four-o'clock

red four o'clock, scarlet four-o'clock

Stems

usually erect or ascending, occasionally decumbent, leafy mostly in proximal 2/3 of plant, openly forked distally, 4–15 dm, basally usually glabrous or puberulent in 2 lines, rarely spreading-pubescent; distally stems usually puberulent in 2 lines, occasionally glabrate, rarely spreading glandular-pubescent.

ascending to erect, 1.5–9 dm, glabrous basally, glabrous or rarely very sparsely puberulent distally.

Leaves

ascending at 45–80°, abruptly reduced to inflorescence;

petiole 0.2–2 cm;

blade green, ovate-lanceolate to ovate or triangular, 3–10 × 2–6.5 cm, usually ± thin, base obtuse, round, truncate, or cordate, apex acute to acuminate, rarely rounded, surfaces usually glabrous, sometimes puberulent or sparsely hispidulous.

usually ascending or spreading at 45–90°, dark grayish green, moderately thick and fleshy;

petiole 0–0.3 cm;

blade linear to linear-lanceolate, 4.5–10 × 0.1–0.5 cm, base attenuate, apex acute, surfaces glabrous or rarely with few small hairs adaxially, glabrous abaxially.

Inflorescences

terminal and in upper axils, subumbellate clusters at ends of long, forked branches;

peduncle 5–20 mm, usually pubescent with ascending, often curved, glandular or eglandular hairs, crosswalls of hairs pale;

involucres pale green, often tinged pinkish, widely bell-shaped to almost rotate, 4–6 mm in flower, 8–15 mm in fruit, glabrous or glabrate but with minute curved hairs on margins, or rarely puberulent or pilose throughout, 50–90% connate, lobes ovate to broadly ovate.

peduncle 4–8 mm, spreading stiff short hairy or glandular-pubescent, crosswalls of hairs pale;

involucres dark green, opaque, moderately veiny, 4–7 mm in flower, 4–8 mm in fruit, softly hirtellous or glandular-hirtellous, bracts 30–40% connate, lobes narrowly ovate or triangular.

Flowers

(2–)3(–5) per involucre;

perianth usually pink to reddish purple, rarely white, 1 cm.

perianth bright red-purple, 1.3–2 cm.

Fruits

dark grayish brown to reddish brown (ribs and tubercles usually slightly paler), narrowly obovate and tapering at both ends, 3.4–5 mm, shaggy-pubescent with spreading, sometimes tufted, hairs, 0.3–0.4 mm, sometimes also with layer of minute hairs;

ribs usually irregularly and deeply notched, especially toward apex, round to bluntly angled, 0.5–0.75 times width of sulci, 0.5–1 times as wide as high;

sulci with pale small to tall tubercles that are sometimes horizontally lengthened and shelflike.

pale olive brown, 4.5–6 mm;

ribs round, 0.5–0.8 times width of sulci, 0.5 times as wide as high, smooth or slightly warty or with warts equaling height of ribs;

sulci smooth.

2n

= 58.

Mirabilis nyctaginea

Mirabilis coccinea

Phenology Flowering late spring–early fall. Flowering late spring–early fall.
Habitat Weedy areas in dry, often disturbed sites Dry, open hillsides of igneous rock, shrubs, pinyon-juniper or mixed conifer woodlands
Elevation 100-2200 m (300-7200 ft) 1200-2000 m (3900-6600 ft)
Distribution
from FNA
AL; AR; AZ; CA; CO; CT; DC; DE; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; ON; QC; SK; Europe [Introduced in Mexico]
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NM; Mexico (Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Mirabilis nyctaginea is considered a noxious weed in some states. The holotype of Mirabilis ×collina Shinners is a hybrid between M. nyctaginea and M. albida. On the Great Plains, M. nyctaginea also appears to intergrade with M. albida. Prominence of the tubercles and redness of the fruits decreases in western populations. Near the Great Lakes, comparatively narrow-leaved plants with sparsely hirsute stems seem to be intergrades between M. nyctaginea and more or less hirsute M. albida. Mirabilis ×serotina Shinners is a hybrid between M. nyctaginea and M. glabra.

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

Mirabilis coccinea is easily confused with M. linearis var. linearis when the flowers are closed. The distinction is more difficult when plants are cleistogamous (phase Allionia gracillima in M. coccinea; phases A. pinetorum and Oxybaphus bodinii in M. linearis). In general, leaves of M. coccinea are oriented at an angle of 45° or greater to the stem, the distal portion of the main axis of the inflorescence is glabrous to 2–3 cm from the flowers, and the peduncles are sparingly short pubescent. In var. linearis, the leaves are generally oriented at 45° or less to the stem, the inflorescence is densely pubescent, and the peduncles are densely spreading-pubescent. Reports of the occurrence of M. coccinea in Texas (e.g., D. S. Correll and M. C. Johnston 1970) are apparently based on literature records and perhaps on a labeling error of a probable isotype collected by Charles Wright. No specimens have been seen from Texas. P. C. Standley (1911) discussed the unique nature of the fruit and perianth of this species relative to sect. Mirabilis and sect. Oxybaphus; in the original description, Torrey noted the species to be intermediate between Oxybaphus and Quamoclidion.

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

Source FNA vol. 4, p. 55. FNA vol. 4, p. 49.
Parent taxa Nyctaginaceae > Mirabilis > sect. Oxybaphus Nyctaginaceae > Mirabilis > sect. Mirabilopsis
Sibling taxa
M. albida, M. alipes, M. austrotexana, M. coccinea, M. gigantea, M. glabra, M. greenei, M. jalapa, M. laevis, M. latifolia, M. linearis, M. longiflora, M. macfarlanei, M. melanotricha, M. multiflora, M. oxybaphoides, M. pudica, M. rotundifolia, M. tenuiloba, M. texensis
M. albida, M. alipes, M. austrotexana, M. gigantea, M. glabra, M. greenei, M. jalapa, M. laevis, M. latifolia, M. linearis, M. longiflora, M. macfarlanei, M. melanotricha, M. multiflora, M. nyctaginea, M. oxybaphoides, M. pudica, M. rotundifolia, M. tenuiloba, M. texensis
Synonyms Allionia nyctaginea, Oxybaphus nyctagineus Oxybaphus coccineus, Allionia coccinea, Allionia gracillima
Name authority (Michaux) MacMillan: Metasp. Minnesota Valley, 217. (1892) (Torrey) Bentham & Hooker f.: Gen. Pl. 3: 3. (1880)
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