Antennaria
Fruct. Sem. Pl. 2: 410, plate 167, fig. 3. 1791.
Perennials or subshrubs (dioecious, gynoecious, or polygamodioecious), (0.2–) 4–25 (–70) cm (sometimes cespitose, sometimes stoloniferous, sometimes rhizomatous). Stems erect. Leaves basal and cauline; alternate; petiolate or sessile; blades (1–7-nerved) mostly cuneate, elliptic, lanceolate, linear, oblanceolate, or spatulate, margins entire, abaxial faces usually tomentose, adaxial glabrous or ± tomentose to sericeous or glabrescent. Heads discoid (unisexual), borne singly or in corymbiform, paniculiform, racemiform, or subcapitate arrays. Involucres: staminate campanulate to hemispheric, 2–6+ mm diam.; pistillate turbinate or campanulate to cylindric, 3–7 (–9+) mm diam. Phyllaries in 3–6+ series, usually relatively narrow, unequal (proximally papery or membranous; distally ± scarious, often black, brown, castaneous, cream, gray, green, olivaceous, pink, red, white, or yellow), apices usually acute, sometimes obtuse to ± truncate. Receptacles flat to convex or ovoid, foveolate, epaleate. Ray-florets 0. Disc-florets mostly 20–100+, (functionally) staminate or pistillate; staminate corollas white, yellow, or red, narrowly funnelform or tubular (lobes usually 5, erect to recurved); pistillate corollas white, yellow, or red, narrowly tubular to filiform. Cypselae mostly ellipsoid to ovoid, faces usually glabrous, often papillate (stout, myxogenic twin-hairs); pappi: falling (bristles basally connate or coherent, shed together in rings or in groups); staminate usually of 10–20+ (usually ± clavate, sometimes capillary, barbellate to barbellulate) bristles; pistillate usually of 12–20+ (capillary, barbellulate to smooth) bristles. x = 14.
Contents
Distribution
Temperate and arctic/alpine regions, North America, Mexico, South America, Eurasia
Discussion
Species 45 (34 in the flora).
Some species of Antennaria, especially the stoloniferous, mat-forming species, are cultivated as rock-garden ornamentals. Among the more suitable species widely used for that purpose are A. dioica, A. microphylla, A. parvifolia, A. rosea, and A. suffrutescens. Clones with red or pink phyllaries have been selected as prized for cultivation. Some species are used in the dried-flower trade.
Phylogenetic relationships within Antennaria. Antennaria is composed of two major lineages: the Leontipes group, mostly restricted to western North America, and the Catipes group, occurring throughout the Northern Hemisphere and South America (R. J. Bayer et al. 1996). The Leontipes group consists of five smaller groups (the Geyerae, Arcuatae, Argenteae, Dimorphae, and Pulcherrimae) and comprises species that are primarily diploid (tetraploids are known only in A. dimorpha and A. pulcherrima, Bayer and G. L. Stebbins 1987, and, as far as is known, always amphimictic, sexually reproducing). Most of the species of the Leontipes group lack horizontal stoloniferous growth (except A. flagellaris and A. arcuata). Morphologically, the Leontipes group is considered primitive in the genus, based on unspecialized morphologic features such as non-stoloniferous growth, lack of extensive polyploidy, and general lack of well-developed sexual dimorphism; the Catipes group has amphimictic diploids and tetraploids. Derived from them are all of the polyploid agamic complexes (fig. 1). Most species of the Catipes group have horizontal stolons, an effective means of asexual reproduction; it is considered more specialized than the Leontipes group.
For the most part, the smaller monophyletic groups composing the Leontipes group correspond to traditionally recognized groups (R. J. Bayer 1990; Bayer et al. 1996). The Geyerae group is monotypic, consisting of Antennaria geyeri, and the tendency toward polygamodioecy in that species, along with its lack of basal leaves, makes it more similar morphologically to Anaphalis than to the remainder of Antennaria. Antennaria arcuata is the only member of the newly recognized Arcuatae group, and it was previously considered to be a portion of the Argenteae along with A. luzuloides and A. argentea (Bayer), a relationship that was always considered weak. The Argenteae group comprises A. argentea, A. luzuloides, and A. stenophylla and is sister to the A. arcuata–A. geyeri clade (Bayer et al.). The Dimorphae group, A. dimorpha and A. flagellaris, is sister to the Geyerae-Arcuatae-Argenteae clade (Bayer et al.), and the Pulcherrimae group comprises A. pulcherrima, A. anaphaloides, and A. lanata (Bayer; Bayer et al.).
The Catipes group is well supported in both morphologic and molecular phylogenetic trees (R. J. Bayer et al. 1996); support for subclades within Catipes is weak. Traditionally, members of Catipes were split into the Alpinae, distributed in tundra, with black or olivaceous phyllaries, and the Dioicae with lighter phyllaries. Based on DNA sequence data and morphology, the two groups are artificial and should be abandoned (Bayer et al.). Amphimixis, apomixis (agamospermy), and high levels of polyploidy (Bayer and T. M. Minish 1993) are prevalent among polyploid derivatives of the Catipes group, which consists of diploids and some tetraploids in which sexual dimorphism is highly evolved (Bayer 1990). Some species of the Catipes group are specialized as edaphic endemics, e.g., Antennaria virginica on Devonian-age shale barrens (Bayer and G. L. Stebbins 1987, 1993), A. suffrutescens on serpentine (Bayer and Stebbins 1993), and A. aromatica and A. densifolia on limestone talus (Bayer 1989). Five polyploid agamic complexes, A. alpina (together with the smaller A. media, A. monocephala, and A. friesiana complexes), A. howellii, A. parlinii, A. parvifolia, and A. rosea, have evolved via multiple hybridization among members of the Catipes group (Bayer 1987, 1997). The great success of the Catipes group seems to be correlated with their ability to grow in diverse habitats throughout their range across Eurasia and North America to Tierra del Fuego in South America, and to their acquisition of characteristics such as strong sexual dimorphism, polyploidy, agamospermy, and vegetative reproduction (stolons). The amphimictic taxa of the Catipes group include A. aromatica, A. corymbosa, A. densifolia, A. dioica, A. friesiana subsp. alaskana, A. friesiana subsp. neoalaskana, A. marginata, A. microphylla, A. monocephala subsp. monocephala, A. neglecta, A. plantaginifolia, A. pulchella, A. racemosa, A. rosulata, A. solitaria, A. suffrutescens, A. umbrinella, and A. virginica. Some of those have contributed to the genetic makeup of the polyploid complexes, whose morphologic variation is correlated to the number of diploid genomes contributed to the origin of the complex. Morphologic overlap between the complexes is a direct consequence of pivotal genomes recurring in some complexes. For example, the A. parlinii and A. howellii complexes share two pivotal genomes from A. plantaginifolia (PLA) and A. racemosa (RAC). Some apomictic clones (identified under the name A. howellii subsp. howellii in part) appear to bridge the morphologic gap between the two complexes. The A. parlinii complex has three diploid progenitors: A. solitaria (SOL), A. plantaginifolia (PLA), and A. racemosa (RAC); the A. howellii complex has five: A. marginata (MAR), A. neglecta (NEG), A. plantaginifolia (PLA), A. racemosa (RAC), and A. virginica (VIR). Antennaria parvifolia has three major progenitors: A. dioica (DIO), A. neglecta (NEG), and A. marginata (MAR); it is likely that high elevation segregates of the complex also contain genomic contributions from A. pulchella (PUL) and/or A. media. Antennaria rosea is morphologically the most diverse of the polyploid complexes and has as its primary progenitors: A. aromatica (ARO), A. corymbosa (COR), A. microphylla (MIC), A. racemosa (RAC), and A. umbrinella (UMB). It is likely that A. marginata (MAR), A. rosulata (ROS), and possibly A. suffrutescens (SUF) have also contributed to the origins of some A. rosea clones. The circumpolar allopolyploid A. alpina complex appears to have its origins from the amphimictic, dark-phyllaried, arctic-alpine taxa including A. aromatica (ARO), A. densifolia (DEN), A. friesiana subsp. alaskana (ALA), A. friesiana subsp. neoalaskana (NEO), A. monocephala subsp. monocephala (MON), and A. pulchella (PUL). Three polyploid complexes, A. friesiana subsp. friesiana, A. media, and A. monocephala subsp. angustata (ANG) appear to be of non-hybrid, autopolyploid origin and are direct polyploid derivatives of A. friesiana (subspp. alaskana and neoalaskana), A. monocephala subsp. monocephala, and A. pulchella, respectively; most polyploids are of multiple hybrid origin from among multiple amphimicts. Antennaria marginata has also given rise to apparent autopolyploid apomictic derivatives.
Key pivotal genomes involved in the origins of the polyploid complexes include Antennaria aromatica, A. marginata, A. neglecta, A plantaginifolia, A. pulchella, and A. racemosa; significant contributions have also been made by A. corymbosa, A. densifolia, A. dioica, A. friesiana, A. microphylla, A. monocephala, A. solitaria, A. umbrinella, and A. virginica.
Classification of Antennaria. Past practice has been to attempt to recognize each agamospecies as a distinct taxonomic entity, usually at species rank. That has led to unwieldy classifications that can be used only by experts on the group. Clearly, that method is unsatisfactory and a more reasonable scheme for classifying polyploid agamic complexes, such as the one advocated by E. Babcock and G. L. Stebbins (1938), should be adopted. R. J. Bayer and Stebbins (1982) were the first to use the Babcock and Stebbins method in Antennaria.
Because the sexual diploids are morphologically discrete, they are each recognized as species. Polyploids that are morphologically identical with sexual diploid (nonhybrid- or auto-polyploid) taxa, whether they are agamospermous or amphimictic, are treated as conspecific with their sexual diploids, e.g., tetraploid cytotypes of Antennaria virginica and some other taxa are treated as conspecific with their corresponding sexual diploids because they are morphologically (R. J. Bayer and G. L. Stebbins 1982) and, in the case of A. virginica, genetically (Bayer and D. J. Crawford 1986) inseparable from the sexual diploids. Sexual and asexual polyploids that are of hybrid origin (segmental and genomic allopolyploids) are recognized as species because their genetic composition is not attributable to any single diploid origin. For example, Bayer and Stebbins classified A. parlinii as distinct from its sexual diploid progenitors, A. plantaginifolia, A. racemosa, and A. solitaria. A. Cronquist (1945) recognized A. parlinii (sensu Bayer and Stebbins) as two varieties of A. plantaginifolia, a view Stebbins and I opposed because the polyploids, while containing genes from A. plantaginifolia in their genetic background, also have genes from A. racemosa and A. solitaria (Bayer 1985b; Bayer and Crawford). The polyploid complexes are each defined primarily by assessing their genomic composition through the use of genetic markers, as well as through morphologic studies. This philosophy and method of classification has been extended to the other polyploid agamic complexes.
Identifying Antennaria specimens. Users of this treatment should be aware that multiple details must be kept in mind when collecting and trying to identify species of Antennaria. For example, assigning specimens to species in the “mat-forming,” stoloniferous Catipes group is particularly difficult because of widespread polyploidy and apomixis. One determinative taxonomic character (whether populations are gynoecious or dioecious) may not be readily observed on herbarium specimens but is readily determined in the field by gender ratios. On herbarium specimens, assuming pistillates are always present in populations, absence of staminates could mean either that they were not collected or that they were actually absent from the population. This character comes into use in separating the infraspecific taxa within both A. monocephala and A. friesiana. If this character cannot be readily determined on herbarium material, i.e., when staminates are absent, then such specimens are best keyed to the specific level only.
Another feature of importance in identifying specimens of Antennaria is the presence or absence of well-developed stolons that root at their tips. Some Antennaria species produce stiff, semi-erect stolons that do not root at the tips, and those stolons should not be confused with the typical stolons that are more elongate and horizontal and root at their tips.
The final feature of importance in identifying specimens of Antennaria is the presence or absence of flags on tips of mid and distal cauline leaves. Flags are flat, linear, scarious appendages of the leaf tips that are similar to the tips of the phyllaries; they are not to be confused with ordinary subulate or blunt leaf tips that are essentially green and herbaceous. In keys and descriptions, leaves are referred to as flagged or not flagged.
Selected References
Lower Taxa
Keys
Key to Groups of Antennaria Species
| 1 | Heads usually borne singly, rarely in 2s or 3s | Group 1 |
| 1 | Heads usually (2–)3–15(–110+), rarely borne singly | > 2 |
| 2 | Stolons none (or erect and not rooting at tips; plants not forming mats; in fruit, heights of pistillate plants ± equal to staminates) | Group 2 |
| 2 | Stolons mostly 1–5(–18) cm (usually prostrate, sometimes ascending, usually rooting at tips; plants forming mats; in fruit, heights of pistillate plants usually greater than or equal to heights of staminates) | > 3 |
| 3 | Basal leaves 3–5(–7)-nerved | Group 3 |
| 3 | Basal leaves mostly 1-nerved (1–3-nerved in A. arcuata and A. marginata) | > 4 |
| 4 | Phyllaries (proximally dark) distally mostly dark to light brown, black, or olivaceous (some times inner whitish); arctic or alpine tundra to just below treeline | Group 4 |
| 4 | Phyllaries (proximally light) distally mostly light brown, cream, gray, green, ivory, pink, red, rose, or white; seldom arctic or alpine tundra (A. corymbosa sometimes alpine) | Group 5 |
Group 1
| 1 | Basal leaves 3–5-nerved; se United States | Antennaria solitaria |
| 1 | Basal leaves 1-nerved; w North America, Arctic | > 2 |
| 2 | Plants 0.2–1.5(–2) cm (heads subsessile among basal leaves); basal leaves silvery gray- pubescent; Arizona, Colorado, New Mexico, Utah | Antennaria rosulata |
| 2 | Plants 0.5–13 cm; basal leaves abaxially gray-tomentose (sometimes none at flowering, A. suffrutescens); usually not Arizona, Colorado, New Mexico, Utah (A. dimorpha sometimes Colorado, New Mexico, Utah) | > 3 |
| 3 | Cauline leaves spatulate (apices emarginate or obtuse), adaxial faces green, gla- brous (bases of plants ± woody); nw California and sw Oregon | Antennaria suffrutescens |
| 3 | Cauline leaves linear or oblanceolate (apices acute to obtuse), adaxial faces green or gray, glabrous or pubescent, sericeous, tomentose, or villous; not nw California or sw Oregon | > 4 |
| 4 | Leaves: adaxial faces green, usually glabrous, rarely villous or pubescent (flags of mid and distal cauline leaves brown); arctic and alpine tundra | Antennaria monocephala |
| 4 | Leaves: adaxial faces gray, sericeous or tomentose (flags of mid and distal cauline leaves none); sagebrush steppe or talus near treeline | > 5 |
| 5 | Stolons none (plants cespitose, not forming mats); semidesert | Antennaria dimorpha |
| 5 | Stolons 0.5–2 or 3–10 cm (plants forming mats); semidesert or limestone talus | > 6 |
| 6 | Gynoecious; stolons 0.5–2 cm (leafy); basal leaves spatulate, rhombic- spatulate, or cuneate; s Nevada | Antennaria soliceps |
| 6 | Dioecious; stolons 3–10 cm (not leafy); basal leaves linear-oblanceolate; not s Nevada | Antennaria flagellaris |
Group 2
| 1 | Plants 7–15 cm (mid and distal cauline leaves flagged); low and high arctic | Antennaria friesiana |
| 1 | Plants either 15–65 cm (low arctic or subalpine) OR 0–70 cm (desert steppe or alpine, except A. pulcherrima arctic) | > 2 |
| 2 | Plants (3–)10–15 cm; basal leaves linear to narrowly oblanceolate (1–3 mm wide); phyl- laries distally light brown, dingy brown, or olivaceous | Antennaria stenophylla |
| 2 | Plants 3–70 cm; basal leaves elliptic, lanceolate, linear, oblanceolate, or spatulate (3–25 mm wide; sometimes none at flowering); phyllaries distally usually brown, cream, pink, red, or white, rarely black, dark brown, castaneous, or olivaceous | > 3 |
| 3 | Phyllaries (scarious, glabrous) | > 4 |
| 3 | Phyllaries (scarious distally, hairy proximally) | > 5 |
| 4 | Basal leaves oblanceolate to elliptic; cauline leaves oblanceolate; pistillate involucres 4–5 mm; phyllaries (usually pale green proximally) distally silvery white | Antennaria argentea |
| 4 | Basal leaves linear to narrowly spatulate; cauline leaves narrowly oblanceolate, narrowly spatulate, or linear; pistillate involucres 3.5–6.5 mm; phyllaries (usually light brown to golden proximally) distally white (often red- or pink-flecked). | Antennaria luzuloides |
| 5 | Basal leaves (absent at flowering; plants woody at bases); phyllaries (densely pubescent to well distal of middle), distally usually pink to red, sometimes light brown or white | Antennaria geyeri |
| 5 | Basal leaves elliptic, lanceolate, oblanceolate, or spatulate; phyllaries (moderately pubescent proximal to middle) distally usually black, brown, castaneous, cream, olivaceous, or white (rarely red- or pink-flecked) | > 6 |
| 6 | Plants 3–20 cm; phyllaries (light brown, dark brown, or olivaceous proximally) distally whitish or light brown; alpine slopes | Antennaria lanata |
| 6 | Plants 8–65 cm; phyllaries (outer usually each with a dark spot at base) distally black, brown, castaneous, cream, olivaceous, or white; mostly subalpine, montane, or subarctic | > 7 |
| 7 | Pistillate involucres 4.5–7 mm; phyllaries (bases each with dark spot 0.1–1 mm) distally cream or white (apices obtuse); dry montane or steppe | Antennaria anaphaloides |
| 7 | Pistillate involucres 7–12 mm; phyllaries (bases each with dark spot 1–3 mm) distally black, brown, castaneous, or olivaceous (apices acute); wet sites, subalpine or subarctic (A. pulcherrima subsp. pulcherrima) or limestone near sea level (A. pulcherrima subsp. eucosma) | Antennaria pulcherrima |
Group 3
| 1 | Basal leaves adaxially glabrous; heads in loose racemiform or paniculiform arrays (stems proximal to heads with purple glandular hairs); w North America | Antennaria racemosa |
| 1 | Basal leaves adaxially gray-pubescent, floccose-glabrescent, or green-glabrescent; heads in tight, corymbiform arrays (stems proximal to heads with or without purple glandular hairs); e North America to e Manitoba, Minnesota, Missouri, Texas | > 2 |
| 2 | Basal leaves abaxially tomentose; pistillate involucres 5–7 mm; staminate corollas 2–3.5 mm; pistillate corollas 3–4 mm (young stolons mostly ascending); Appalachians, Pied- mont, Atlantic seaboard, and driftless area of Wisconsin, Minnesota | Antennaria plantaginifolia |
| 2 | Basal leaves adaxially tomentose or glabrous; pistillate involucres (7–)8–13 mm; staminate corollas 3.5–5 mm; pistillate corollas 4–7 mm (young stolons mostly decumbent); e North America from Atlantic seaboard to e margin of Great Plains | Antennaria parlinii |
Group 4
| 1 | Stolons 0.5–2.5 cm (prostrate); basal leaves usually cuneate, cuneate-spatulate, or spatulate, sometimes oblanceolate (lengths 1–2 times widths); limestone talus, n Wyoming to Yukon and Northwest territories | > 2 |
| 1 | Stolons 0.1–16 cm (erect or decumbent); basal leaves cuneate, linear-cuneate, oblanceolate, or spatulate (lengths 2–6+ times widths); not limestone talus, w North America, Arizona, New Mexico to circumpolar Arctic | > 3 |
| 2 | Basal leaves mostly 5–16 × 3–10 mm; distal cauline leaves not flagged; pistillate involucres 5–7(–9) mm (living plants with odor of citronella when crushed; flowering stems, leaves, and bases of phyllaries stipitate-glandular) | Antennaria aromatica |
| 2 | Basal leaves mostly 3–7 × 2–5 mm; mid and distal cauline leaves flagged; pistillate involucres 4.5–7.5 mm (living plants odorless; flowering stems, leaves, and bases of phyllaries not stipitate-glandular) | Antennaria densifolia |
| 3 | Stolons (usually erect, slightly woody); phyllaries distally pale brown, white, or yellowish (sometimes streaked with pink or rose, usually blunt); montane, rarely above treeline. | Antennaria umbrinella |
| 3 | Stolons (usually decumbent, herbaceous); phyllaries distally black, brown, or olivaceous (sometimes whitish at tips, usually acute); arctic, alpine, rarely subalpine | > 4 |
| 4 | Cauline leaves 3–11(–13) mm; staminate corollas 1.9–2.8 mm; pistillate corollas 2–3 mm (stems, leaves, and phyllaries often stipitate-glandular); Sierra Nevada (Lake Tahoe to Mt. Whitney), California, adjacent Nevada | Antennaria pulchella |
| 4 | Cauline leaves 4–20 mm; staminate corollas 2.5–4.5 mm; pistillate corollas 3–4.5 mm (stems, leaves, and phyllaries stipitate-glandular or not); w North America (Arizona, California, New Mexico n to Yukon, Northwest Territories, e Arctic) | > 5 |
| 5 | Basal leaves: faces gray-pubescent; mid and distal cauline leaves mostly not flagged (sometimes flagged near heads) | Antennaria media |
| 5 | Basal leaves: abaxial faces tomentose, abaxial green-glabrescent to gray-pubescent; mid and distal cauline leaves flagged | > 6 |
| 6 | Stolons 0.1–4 cm; involucres: pistillate 5.5–8 mm; corollas: staminate 2.5–3 mm, pistillate 3–4.5 mm (stems, leaves, and phyllaries stipitate-glandular, hairs purple). | Antennaria friesiana |
| 6 | Stolons 1–7 cm; involucres: pistillate 4–7(–10) mm; corollas: staminate 3–3.5 mm, pistillate 3.5–5 mm (stems, leaves, and phyllaries not stipitate-glandular) | Antennaria alpina |
Group 5
| 1 | Basal leaves adaxially usually green-glabrous, sometimes gray-pubescent; phyllaries distally brown, pink, or white | > 2 |
| 1 | Basal leaves usually adaxially pubescent, sometimes glabrous or glabrate with age (A. neglecta); phyllaries distally black, brown, cream, green, ivory, pink, red, stramineous, white, or yellow (sometimes streaked with pink or rose) | > 5 |
| 2 | Basal leaves 1–3-nerved, 9–12 mm wide; distal cauline leaves flagged; phyllaries distally usually light brown, sometimes white | Antennaria howellii |
| 2 | Basal leaves 1-nerved, 3–9 mm wide; distal cauline leaves flagged or not; phyllaries distally whitish or pink | > 3 |
| 3 | Distal cauline leaves flagged; phyllaries distally white or cream; e, c North America | Antennaria howellii |
| 3 | Distal cauline leaves not flagged; phyllaries distally white or light to dark pink; sw United States, Alaska (Aleutian Islands) | > 4 |
| 4 | Stolons (pubescent) 2–5 cm (stems not stipitate-glandular); basal leaves adaxially green-glabrous (margins not white-woolly); Alaska (Aleutian Islands) | Antennaria dioica |
| 4 | Stolons (densely woolly, hairs obscuring surfaces) 2–7 cm (stems sometimes stipitate-glandular, hairs white or purplish); basal leaves adaxially green-glabrous (margins white-woolly); Arizona, se California, sw Colorado, New Mexico | Antennaria marginata |
| 5 | Basal leaves (largest 20–65 × 6–20 mm); phyllaries distally light brown, ivory, or white (never black, dark brown, dark green, pink, or red) | > 6 |
| 5 | Basal leaves (largest mostly 16–45 × 4–15 mm; if 20+ mm long, less than 6.5 mm wide; if 6.5+ mm wide, less than 20 mm long); phyllaries distally light to dark brown, ivory, pink, red, rose, or white | > 7 |
| 6 | Basal leaves cuneate-oblanceolate, narrowly to broadly ovate, spatulate, or spatulate-obovate, 20–48(–65) × 2.5–20 mm, abaxially tomentose, adaxially gray-pubescent or green-glabrous; mid and distal cauline leaves mostly not flagged (sometimes flagged near heads) | Antennaria howellii |
| 6 | Basal leaves cuneate-oblanceolate to spatulate, 15–65 × 6–18 mm, abaxially tomentose, adaxially gray-pubescent (green-glabrescent in age); mid and distal cauline leaves flagged | Antennaria neglecta |
| 7 | Stolons either 4–10 cm (herbaceous, arched) or 4–16 cm (slightly woody, erect); phyllaries distally usually pale brown, sometimes whitish or yellowish (rarely white- or pink-flecked) | > 8 |
| 7 | Stolons 1–10 cm (herbaceous, usually decumbent); phyllaries distally usually cream, gray, green, pink, red, stramineous, white (ivory to pure), or yellow (if light brown, staminate plants absent from populations) | > 9 |
| 8 | Stolons 4–16 cm (somewhat woody, usually erect); basal leaves narrowly spatulate to cuneate, 10–17 × 2–5.4 mm (plants woody at bases); Alberta and British Columbia to California and Colorado | Antennaria umbrinella |
| 8 | Stolons 4–10 cm (herbaceous, arched); basal leaves narrowly to broadly spatulate or rhombic-ovate, 20–45 × 3–15 mm; Blaine County, Idaho, Elko County, Nevada, and Fremont County, Wyoming | Antennaria arcuata |
| 9 | Plants 2–8(–15) cm; pistillate involucres 8–10(–15) mm | Antennaria parvifolia |
| 9 | Plants 4–30 cm; pistillate involucres 4–10 mm | > 10 |
| 10 | Basal leaves spatulate; phyllaries (each with chestnut brown spot near base) distally white or light brown (willow thickets, similar moist habitats, subalpine to alpine zones, Rocky Mountains and c Sierra Nevada) | Antennaria corymbosa |
| 10 | Basal leaves cuneate-oblanceolate, spatulate, or linear; phyllaries (uniformly or combinations of) light brown, cream, gray, green, pink, red, white, or light yellow | > 11 |
| 11 | Gynoecious (staminate plants very rare); basal leaves linear; phyllaries distally usually (combinations of) light brown, cream, gray, green, pink, red, white, or yellow (if solid white, not Appalachian) | Antennaria rosea |
| 11 | Dioecious (stems sometimes stipitate-glandular distally); basal leaves cuneate-oblanceolate or spatulate; phyllaries distally stramineous, white, or light yellow | > 12 |
| 12 | Basal leaves 10–25 × 3–9 mm, faces gray-pubescent; shale barrens, e Ohio, w Pennsylvania, Maryland, Virginia, West Virginia | Antennaria virginica |
| 12 | Basal leaves 6–16 × 2–6 mm, faces silvery white-pubescent (stems stipitate-glandular distally, hairs purple or white, moniliform); w North America e to Ontario | Antennaria microphylla |