Zinnia grandiflora
Zinnia
plains or Rocky Mountain zinnia, plains zinnia, Rocky Mountain zinnia, Rocky Mountains zinnia
zinnia
greenish, much branched, strigillose.
prostrate or erect.
blades 1- or 3-nerved (some larger leaves), linear, 10–30 × 2–3 mm, strigose to scabrous.
cauline; opposite or subopposite;
sessile [petiolate];
blades (1-, 3-, or 5-nerved from bases) acerose, elliptic, lance-linear, lanceolate, linear, oblong, or ovate, bases rounded to cuneate, margins entire, faces hairy (often scabrous or scabrellous), usually gland-dotted.
to 11 mm.
narrowly campanulate to cylindric, 5–8 × 5–8 mm.
campanulate, cylindric, to hemispheric or broader, 5–25 mm diam.
conic, paleate (paleae yellowish, often reddish to purplish distally, chartaceous to scarious, conduplicate, apices rounded to acute, sometimes fimbriate).
3–6;
corollas bright yellow, laminae ovate to orbiculate, mostly 10–18 mm.
usually 5–21 (more in “double” cultivars, sometimes 0 in Z. anomala), pistillate, fertile;
corollas yellow, orange, red, maroon, purple, or white (laminae persistent, sessile or nearly so, becoming papery, sometimes much reduced).
18–24;
corollas red or green, to 10 mm, lobes 1 mm.
20–150+, bisexual, fertile;
corollas usually yellow to reddish, sometimes purple-tinged, tubes much shorter than cylindric throats, lobes 5, lance-ovate (usually unequal, usually villous or velutinous adaxially).
oblong, often becoming scarious, glabrous or appressed-hairy distally, apices obtuse, erose-ciliate (red-tipped).
persistent, 12–30+ in 3–4+ series (orbiculate to obovate or oblong, unequal, often colored or dark-banded distally, outer shorter).
usually radiate (rarely ± discoid in Z. anomala), borne singly.
4–5 mm, 3-angled (ray) or angular or compressed (disc), ribbed, scabrellous;
pappi 0 or of (1–)2(–4) unequal awns.
3-angled (ray) or flattened (disc; not winged);
pappi 0, or persistent, of 1–3(–4) awns or toothlike scales.
yellowish (often red-tipped), apices obtuse, erose.
= 12 (11, 10).
= 42.
Zinnia grandiflora
Zinnia
Species ca. 17 (5 in the flora).
A. M. Torres (1963) recognized subg. Diplothrix, comprising six species, including the three perennial species treated here, and subg. Zinnia, comprising 11 species, mostly annuals. This division is reflected in the first couplet of the key.
Zinnia angustifolia Kunth (= Z. linearis Bentham), native to northern and western Mexico, is commonly grown as an ornamental in the United States and has been reported from Utah (S. L. Welsh et al. 1993); the record was likely from a cultivated source. The species also persists in gardens in California; it is not known outside of cultivation. It can be distinguished from other zinnias by the combination of annual habit, plants to 50 cm, leaf blades linear to narrowly elliptic (mostly 2–7 cm × 4–8 mm), involucres mostly hemispheric, usually much less than 1 cm high or wide, bright orange ray corollas (white-rayed and other color variants known in cultivation), and lobes of disc flowers glabrous or nearly so. Hybrids between Z. angustifolia and Z. violacea are known in the horticultural trade.
The lack of articulation of the corolla tubes in the ray florets of Zinnia verticillata Andrews (= Z. peruviana) and the bilateral disposition of vascular bundles (continuous with vasculature of the ovary walls) in the ray florets led D. Don (1830) to conclude that true ray “corollas” in Zinnia are lacking, being replaced instead by de novo petaloid structures that mimic ray corollas of other Compositae.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Annuals, 30–50(–200) cm; leaf blades elliptic, lanceolate, oblong, or ovate; involucres campanulate, or hemispheric or broader, 10–25 mm diam | → 2 |
1. Subshrubs, to 22 cm; leaf blades linear to acerose; involucres narrowly campanulate, cylindric, or subhemispheric, 5–10mm diam | → 3 |
2. Involucres narrowly to broadly campanulate, 9–18 × 10–20 mm; paleae apically obtuse, erose or subentire; pappi usually of 1 awn (disc cypselae) | Z. peruviana |
2. Involucres hemispheric or broader, 10–15 × 15–25 mm; paleae apically fimbriate; pappi 0 | Z. violacea |
3. Leaf blades 1-nerved, linear to acerose; ray florets 4–7, corollas usually white, sometimes pale yellow | Z. acerosa |
3. Leaf blades 1- or 3-nerved (some larger leaves), linear; ray florets usually 5–8, corollas usually yellow (laminae sometimes 0) | → 4 |
4. Involucres 8–10 mm; ray laminae 0–6(–9) mm | Z. anomala |
4. Involucres 5–8 mm; ray laminae mostly 10–18 mm | Z. grandiflora |
KS Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
OR
Flora NW
PNW Herbaria
