This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available (e.g., [5,55,57,62,67,71,79,94,138]).
Aboveground description: Hood's phlox is a small, low-growing, mat-forming, perennial [62,68]. There is considerable variability in botanical characteristics, which is only partially reduced by the recognition of subspecies. Descriptions of compact matted and loosely caespitose growth forms are described [5,55]. The woody root crown or caudex produces multiple branches [5,138]. Plants are typically hairy and measure between 2 and 12 inches (5-30 cm) across and less than 5 inches (13 cm) tall [4,68,71,79,94,95]. Plants monitored for 8 years in southwestern North Dakota averaged 1.8 inches (4.6 cm) tall. Maximum and minimum heights were 2.4 inches (6.0 cm) and 1.2 inches (3.0 cm), respectively [54]. Branches are crowded with nodes and dense with leaves [18,67,94,95]. Spiny phlox is a stress-tolerant species with slow leaf turnover [17]. Early spring growth is rapid, and plants normally mature before associated vegetation grows to an "appreciable height" [22,54].
Leaves occur opposite one another and are described as woolly or loosely pubescent, with long tangled or cobwebby hairs [5,18,67,68,137]. Leaves are narrow, firm, pungent, and needle-like with sharp points; often the mid-rib is thickened [4,62,79]. Degree of leaf overlap varies, and leaves are typically ascending [35,55,137]. Leaves normally range from 0.1 to 0.5 inch (3-13 mm) long and less than 1 mm wide at the midpoint [37,55,57,79,137]. Old leaves are persistent [4]. Flowers are most often solitary and appear at the ends of branches [5,67,94]. Petals are 5 lobed and range from white to pale blue, purple, or pink [35,57,62]. Petal lobes are typically 0.16 to 0.28 inch (4-7 mm) long, and the flower tube measures 0.24 to 0.47 inch (6-12 mm) long [18,62]. Seeds are normally 0.08 to 0.1 inch (2-3 mm) long [18].
Belowground description: Spiny phlox produces coarse woody taproots [35,57,62,95]. Roots excavated from a sagebrush-dominated site in western Colorado tested positive for mycorrhizal associations [105].
Taproots penetrate deeply if soil depth permits, and lateral roots are short. Maximum root penetration was 36 inches (91 cm) in a pristine big sagebrush/mixed grass community in southern Idaho [65]. In mixed prairie of southwestern Saskatchewan, taproots reached depths of 12 to 37 inches (30-95 cm). Root diameters were 1 to 5 mm near the soil surface but decreased to approximately 0.5 mm at 8 to 10 inch (20-25 cm) soil depths. Lateral roots occurred singly or in groups of 2 to 5 at soil depths below 2 to 4 inches (5-10 cm). Lateral roots had diameters of 0.3 to 0.5 mm and were short (≤2 cm). Occasionally plants produced 1 to 2 large secondary taproots that penetrated as deep as the primary taproot. Penetration depths were greatest in well-developed soils on level sites or on lower slope positions. The average maximum root depths were 34 inches (86 cm) and 12 inches (30 cm) on lower and upper slopes, respectively. In shallow soils, roots did not penetrate beyond 12 inches (30 cm). In sandy soils, roots typically penetrated less than 16 inches (41 cm), but lateral roots were more dense and widely spread than those in fine textured soils [36].
The wide range in plant, leaf, and flower size and form is reduced slightly with the recognition of spiny phlox subspecies. Often subspecies descriptions are made in relation to another subspecies. For more information on distinguishing subspecies, see [37,55,57,61,62,71,88,94,100,137,138].
Spiny phlox occurs in western North America and reaches its northern limit in Alaska. Its range extends east to Saskatchewan, western North and South Dakota, and western Nebraska. The southern limit is reached in Arizona, and spiny phlox occurs in the Pacific Coast states but is absent from extreme coastal locations [72,109,138].
Plants Database provides a distributional map of spiny phlox and the following subspecies: Phlox hoodii ssp. canescens, P. h. ssp. glabrata, P. h. ssp. hoodii, P. h. ssp. lantana, P. h. ssp. muscoides, P. h. ssp. viscidula. For more detailed descriptions of the distributions of P. h. ssp. canescens and P. h. ssp. muscoides, see [37,61].
Fire adaptations: Spiny phlox regenerates vegetatively following fire and is common in early postfire communities [1,3,31,102]. Spiny phlox sprouts from the base or caudex and survives most fires [143]. In southeastern Idaho's Power County, spiny phlox emerged from soil collected on burned sites [1]. Postfire regeneration likely includes germination and establishment from on-site and/or off-site seed sources.
FIRE REGIMES: Western sagebrush (Artemisia spp.) and grassland communities are common spiny phlox habitat. Average fire frequency in sagebrush/grassland vegetation is estimated at 32 to 70 years [142]. However, in the black sagebrush range type, wildfire is considered relatively rare due to the low fuel continuity [128]. Low sagebrush vegetation is also thought to burn less often than big sagebrush types because fuel cover is sparse [129]. In many sagebrush vegetation types including Wyoming big sagebrush- and stiff sagebrush-dominated communities, nonnative cheatgrass (Bromus tectorum) is an important associated species. Cheatgrass invasion tends to increase fine fuel loading and continuity [126,130], and has likely increased fire frequency beyond presettlement intervals [99,140].
The following table provides fire return intervals for plant communities and ecosystems where spiny phlox is important. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Community or Ecosystem Dominant Species Fire Return Interval Range (years) bluestem prairie Andropogon gerardii var. gerardii-Schizachyrium scoparium <10 [76,97] Nebraska sandhills prairie Andropogon gerardii var. paucipilus-Schizachyrium scoparium <10 [97] silver sagebrush steppe Artemisia cana 5-45 [60,101,141] sagebrush steppe Artemisia tridentata/Pseudoroegneria spicata 20-70 [97] basin big sagebrush Artemisia tridentata var. tridentata 12-43 [110] mountain big sagebrush Artemisia tridentata var. vaseyana 15-40 [9,25,89] Wyoming big sagebrush Artemisia tridentata var. wyomingensis 10-70 (x=40) [134,144] saltbush-greasewood Atriplex confertifolia-Sarcobatus vermiculatus <35 to <100 [97] plains grasslands Bouteloua spp. <35 [97,141] blue grama-needle-and-thread grass-western wheatgrass Bouteloua gracilis-Hesperostipa comata-Pascopyrum smithii <35 [97,108,141] cheatgrass Bromus tectorum 99,140] curlleaf mountain-mahogany* Cercocarpus ledifolius 13-1,000 [11,112] mountain-mahogany-Gambel oak scrub Cercocarpus ledifolius-Quercus gambelii <35 to <100 western juniper Juniperus occidentalis 20-70 Rocky Mountain juniper Juniperus scopulorum <35 [97] wheatgrass plains grasslands Pascopyrum smithii <5-47+ [97,101,141] pinyon-juniper Pinus-Juniperus spp. <35 [97] Rocky Mountain bristlecone pine P. aristata 9-55 [42,43] Colorado pinyon Pinus edulis 10-400+ [51,56,73,97] interior ponderosa pine* Pinus ponderosa var. scopulorum 2-30 [8,13,81] Arizona pine Pinus ponderosa var. arizonica 2-15 [13,34,114] mountain grasslands Pseudoroegneria spicata 3-40 (x=10) [7,8] Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [8,9,10] little bluestem-grama prairie Schizachyrium scoparium-Bouteloua spp. <35 [97] *fire return interval varies widely; trends in variation are noted in the species reviewBased on the available information on spiny phlox and fire, recovery of spiny phlox is likely following most fires. However, the lack of information on the response of spiny phlox to successive fires makes it difficult to predict its ability to persist in areas dominated by cheatgrass with high fire frequencies.
Postfire management may impact spiny phlox recovery. Low spiny phlox cover was reported on 3-year-old burned sites in pinyon-juniper (Pinus-Juniperus spp.) and big sagebrush communities that were drill or aerial seeded following a wildfire in central Utah. Coverage of spiny phlox was 0 on one burned and seeded site and 0.4% on another. Sites burned in July, but fire characteristics were not reported. Seeded species included wheatgrasses (Elymus spp.), sweet clover (Melilotus spp.), and alfalfa (Medicago spp.) among others [30].
Throughout its range, spiny phlox occupies dry, open, rocky, gravelly, or sandy sites [4,41,62,67,68,72,95].
Specific characteristics are described for several areas where spiny phlox is common. Near Saskatoon, Saskatchewan, spiny phlox importance values were greatest on the upper and middle positions on eastern to southern slopes. From May to September soil temperatures on upper and middle southern slopes averaged 81 °F (27 °C), and average soil moisture content was 7.9% and 5.3%, respectively. Spiny phlox importance changed dramatically with relatively minor changes in aspect and position [12].
In Eagle, Alaska, spiny phlox occurred in fringed sagebrush (Artemisia frigida)/bluebunch wheatgrass steppe vegetation but not in forested vegetation dominated by quaking aspen (Populus tremuloides), balsam poplar (P. balsamifera), and white spruce (Picea glauca). Environmental conditions were different in the 2 habitats. Soil moisture was lower and soil temperature was higher in steppe vegetation than in the forests. Steppe vegetation received 93.9% full sun and forests received 57%. Litter cover was 5% in steppe vegetation and 79% in forests [139].
Spiny phlox was common on glacial moraines in northwestern Montana's Upper Blackfoot Valley and reached its greatest frequency on the upper part of southern slopes. Summer soil moisture content averaged 11% on upper slopes, less than that of lower slope positions. Temperatures were higher and temperature fluctuations were greatest on southern slopes [16].
Spiny phlox is most typical in sagebrush habitats. Characteristics of some of these habitats are summarized below.
Rangeland cover type ElevationClimate: Spiny phlox primarily occupies sites with continental climates. Conditions are typically dry, and a wide range of temperatures are possible. In North Dakota, Hood's phlox occurs in the west where arid conditions prevail [109]. Parker [95] reports that spiny phlox occupies sites that receive 15 to 20 inches (380-510 mm) of annual precipitation. However, spiny phlox occurs in steppe vegetation in Eagle, Alaska, where annual precipitation averages 12.1 inches (308 mm) and average January and July temperatures are -9.4 °F (-23 °C) and 59 °F (15 °C), respectively [139]. In areas near Saskatoon, Saskatchewan, where spiny phlox occurs, snow is typical from November to March and contributes 30% to the total annual precipitation. Summer temperatures over 100 °F (38 °C) and winter lows of -40 °F (-40 °C) have been recorded for this area [12]. In the Laramie Basin of Wyoming, precipitation averages 11.2 inches (284 mm), and January and July temperatures average 22.4 °F (-5.3 °C) and 64 °F (17.8 °C) [49]. Spiny phlox is sparsely distributed on the Dickinson Experimental Station in southwestern North Dakota, where winters are long and cold, and summers are short and hot. Based on a 70-year record, annual precipitation averaged 15.5 inches (394 mm), and June temperatures averaged 61.4 °F (16.3 °C) [54].
A number of studies indicate that spiny phlox is restricted to sites with early snow melt. Spiny phlox was rarer on sites with late snow melt dates than on sites with early melting dates on the Bangtail Mesa near Bozeman, Montana [136]. Spiny phlox was common (presence 56%) on sites with a snow melt date of 15 May in southwestern Montana; spiny phlox presence decreased as snow cover remained longer. Presence was 27% on sites with a 1 June melt date, and spiny phlox was absent from sites with melt date of 15 June or later [90]. In central Wyoming's Owl Creek range, spiny phlox was present on windblown sites in threetip sagebrush-dominated sites but was absent from sites where deep snow drifts were common [50].
Elevation: Spiny phlox is common at middle and high elevations throughout its range. Narrower elevational ranges by state and variety are provided below:
State/region Variety, if applicable Elevation in feet Arizona 4,000 [72] California P. h. ssp. canescens 4,500-8,900 [61,94] P. h. ssp. lantana 4,000-6,000 [94] P. h. ssp. muscoides 4,600-8,900 [61] New Mexico P. h. ssp. canescens 5,000-7,000 [88] Nevada 4,500-8,000 P. h. ssp. lantana 6,500-8,000 P. h. ssp. muscoides 5,600-8,000 [71] Uinta Basin, Utah 4,800-8,400 P. h. ssp. muscoides ~7,100 [55] Utah 4,000-6,700 [95] P. h. ssp. canescens 4,790-10,700 P. h. ssp. muscoides 4,590-6,910 [138]Soils: Spiny phlox persists on a variety of soil types; however, it commonly occurs on dry, coarse textured soils. In the northern Great Plains and in Utah, Hood's phlox occurs on gravelly, rocky, or sandy soils [57,95]. In grasslands of southwestern Saskatchewan, Hood's phlox was most closely associated with clay and loam soils and was present on fine sandy loams, loams, and clay loams [64]. In steppe vegetation of central Montana, spiny phlox cover and constancy were "consistently" higher on fine-textured soils, and spiny phlox showed little preference for position along a gradient of 0.4 to 4 inches (1-10 cm) of water storage capacity [59]. Spiny phlox was most common on windward exposures where soil moisture was lowest in sagebrush steppe vegetation at Wyoming's Stratton Sagebrush Hydrology Study Area [24]. In Utah, spiny phlox coverage was significantly greater (p≤0.01) on crest than mid-slope or base sites. Crest sites were the most xeric and had the shallowest soils, which averaged 8 inches (20 cm) deep. Clay content was significantly lower and sand and exposed rock were significantly greater on crest than mid-slope or base positions [21].
Spiny phlox is considered a relatively unpalatable species. However, it is utilized to some extent by big game and small mammals. Livestock use of spiny phlox is limited to domestic sheep grazing.
Domestic sheep: Use of spiny phlox by domestic sheep is occasional. Primarily flowers are consumed [68], and some researchers indicate that sheep "relish" spiny phlox flowers [72].
Deer: Several studies report utilization of spiny phlox by mule deer although it rarely contributes much to their overall diet. Spiny phlox was an important November food source for mule deer in Fergus County, Montana [85]. In Montana's Gallatin Canyon, mule deer use of Hood's phlox was light in the winter. Its use was not observed in January or February, but 2% of March feeding observations were on spiny phlox [33].
Researchers observed tame mule deer feeding on spiny phlox in the early spring in a Colorado pinyon-Utah juniper/mixed shrub winter range in Colorado's Piceance Basin. Spiny phlox made up a high of 3% of observations made in April and a high of 4% in March over the course of 2 years on 2 sites. Utilization of spiny phlox was little to none from October through January [14]. Feeding observations on a bighorn sheep winter range in Idaho's East Fork of the Salmon River revealed use by mule deer but not by bighorn sheep. Spiny phlox made up 2.9% of the total instances of mule deer use in February in Wyoming big sagebrush/bluebunch wheatgrass vegetation. In big sagebrush/bluebunch wheatgrass-Sandberg bluegrass vegetation, spiny phlox use was 5.3% in January, 2.5% in February, 0.3% in March, and 0.2% in April [80].
Elk: Spiny phlox abundance on protected sites exceeded that on grazed sites, although differences were not statistically (p>0.05) significant on the northern winter range in Yellowstone National Park. Elk were the primary grazers in the area. The researcher suggested that elk may have utilized spiny phlox when it was actively growing [118].
Pronghorn: Spiny phlox is common in pronghorn habitats, but use of spiny phlox is limited. On rangelands in Yellowstone National Park that are used year round by pronghorn, spiny phlox was common [113]. Pronghorn in Wyoming's Red Desert used big sagebrush habitats extensively. The density of half-shrubs including spiny phlox were significantly (p=0.002) greater on high use than on low use winter sites. Feeding observations and fecal analyses revealed a low level of forbs in pronghorn diets, but species were not identified [38].
In Petroleum County, Montana, researchers observed pronghorn feeding on spiny phlox 0.9% of the time. Use of spiny phlox was restricted to the spring season [32]. One percent of the rumen contents of pronghorn collected in the summer from sagebrush/grasslands in the Cypress Hills of Saskatchewan was spiny phlox. None of the stomachs from pronghorn collected in the Matador Hills contained spiny phlox and none of the stomachs collected in fall, winter, or spring from the Cypress Hills contained spiny phlox. Pronghorn populations were fairly large in Cypress Hills [39].
Bighorn sheep: Utilization of spiny phlox by bighorn sheep is low. spiny phlox was less than 0.5% by volume of the contents of 15 bighorn sheep stomachs collected in October and November in the Sun River area of west-central Montana [111].
Small mammals: spiny phlox seed and leaves are consumed by a variety of small mammals. Mountain cottontail and bushy-tailed woodrat diets were evaluated from feces collected near the Idaho National Engineering and Environmental Laboratory in south-central Idaho. Spiny phlox was not detected in bushy-tailed woodrat feces but made up 1.6% of the relative density of mountain cottontail feces [69]. In South Dakota's Buffalo Gap National Grassland, black-tailed prairie dogs fed on spiny phlox in the winter. At most other times of the year, however, spiny phlox was avoided. Decreased water availability and stressful winter feeding conditions were thought to contribute to diet changes that were evaluated through stomach analyses [48].
Controlled food preference studies indicated that spiny phlox seeds are consumed by deer mice and Great Basin pocket mice in eastern Washington. Mice were presented a known quantity of spiny phlox seed and seed capsules. All of the seed capsules presented on the surface of the sand were consumed by both species. All of the seed presented to Great Basin pocket mice was consumed. Deer mice consumed all but about 15% [74].
Birds: Numerous bird species reside in or visit spiny phlox habitats, but information on the specific use of spiny phlox by birds is lacking. Many bird species were found in mixed grasslands in Wyoming's Laramie Basin during a 3 year census. Mountain plovers, horned larks, and McCown longspurs utilized the area for breeding. Many other birds visited the area, including turkey vultures, red-tailed hawks, ferruginous hawks, marsh hawks, sparrow hawks, killdeer, California gulls, cliff swallows, barn swallows, rock wrens, common nighthawks, western meadow larks, lark buntings, and vesper sparrows. Specific utilization of spiny phlox was not reported [49].
Spiny phlox was common in big sagebrush habitats utilized by sage-grouse in Jackson County, Colorado, for nesting, strutting, and spring and summer feeding. Feeding observations, however, were not species specific [53]. Spiny phlox was considered a nonpalatable forb during a study of sage-grouse in southeastern Alberta [2]. In the Strawberry Valley of north-central Utah, spiny phlox coverage was significantly greater (p<0.05) in sage-grouse nesting areas than in brooding habitats or adult use areas [23].
Palatability/nutritional value: The palatability and forage value of spiny phlox are considered low [92,95]. Dittberner and Olson [40] rate spiny phlox palatability as poor for cattle and horses. Palatability ranges from poor to fair for domestic sheep and elk, poor to good for pronghorn, mule deer, and white-tailed deer, fair for small mammals, poor to fair for game birds, and fair for nongame birds in North Dakota, Montana, Wyoming, Utah, and Colorado.
Cover value: Spiny phlox grows very low to the ground and likely provides cover for only the smallest wildlife species and for insects.
While spiny phlox is common in sagebrush and mountain grassland communities in the
western United States, it is rarely named as a dominant in vegetation types. Below
are vegetation classifications where spiny phlox is recognized as a dominant or
subdominant.
Montana:
prairie Junegrass (Koeleria macrantha)-spiny phlox association, also known as the Koelerietum
Phloxetosum association on glacial till in Glacier County [84]
Spiny phlox begins growing and matures earlier than most associated vegetation. Below are flowering dates by state or region, and by subspecies:
In central Montana, spiny phlox growth begins in early spring [132]. In southwestern North Dakota, seasonal development of spiny phlox was monitored for 8 years. The earliest bloom date was 28 April, and the average earliest bloom date was 24 May. Plants attained 93.3% of total growth in May and 100% of their growth by June [54]. Spiny phlox plants on the Carey Kipuka in southern Idaho are fully grown between 25 May and 5 June [65].
On an experimental farm in Swift Current, Saskatchewan, spiny phlox flowering dates were recorded for 13 years. The earliest spiny phlox was found in flower on 30 April, and the latest date of 1st flowering was 11 May. The latest date spiny phlox was found in flower was 7 July. The average flowering period was 36 days [22]. In southern Saskatchewan and southeastern Alberta, spiny phlox growth begins in the 1st or 2nd week in April. Flowers are common in late April; seed is typically ripe by mid-June. If soil moisture is "sufficient," spiny phlox may flower again in August [35]. A second flowering period is also noted following summer rains in Arizona [72].Spiny phlox regenerates sexually through seed production [95] but can regenerate vegetatively following aboveground damage [1].
Pollination: Most phlox (Phlox spp.) are pollinated by Lepidoptera species. Phlox hoodii ssp. muscoides is pollinated by long-tongued bees [37].
Breeding system: The presence of insect pollinators suggests that cross pollination may predominate.
Seed production: Information regarding spiny phlox seed production is scant. Stevens [123] reported that 50 seeds/plant were produced by mature, average-sized plants growing in a "low competition" area in North Dakota. Seed was collected in seed traps in harvested singleleaf pinyon-Utah juniper (Pinus monophylla-Juniperus osteosperma) stands in west-central Nevada. Abundance of seeds captured was not reported, and seeds were only collected from western aspects, although there were traps on north and south slopes as well [45].
Seed dispersal: Spiny phlox seed is small [18] and could easily be transported by wind. Small mammals may also disperse spiny phlox seed [74].
Seed banking: Several studies indicate that spiny phlox produces a seed bank; however, information regarding seed longevity and persistence in the soil is lacking. Spiny phlox emerged from a bluebunch wheatgrass-blue grama (Pseudoroegneria spicata-Bouteloua gracilis) community after treatment with glyphosate herbicide that killed all plants, indicating emergence from soil-stored seed [27].
Spiny phlox emerged from soil collected in a Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) community. Soil was collected from 4 sites, each with an undisturbed area and an adjacent area ploughed and seeded to crested wheatgrass (Agropyron cristatum) 20 years before the study. Seeded sites 1 and 2 were relatively stable, and seeded sites 3 and 4 were being colonized by native vegetation. Spiny phlox coverage and seedling emergence were greatest in undisturbed sites. The relative cover of and relative seedling emergence of spiny phlox on seeded and undisturbed sites is summarized below [86]:
Relative cover (%)¹ Relative seedling emergence (%)² undisturbed seeded undisturbed seeded Site 1 0.52 0 0.37 0 Site 2 7.57 0.28 1.13 0.08 Site 3 12.86 0.45 3.16 0 Site 4 2.35 0 0.08 0 ¹Spiny phlox cover/total vegetation cover, expressed as a percentageA low number of spiny phlox seedlings emerged from soil collected from 1-year-old burned and unburned sites in Power County, southeastern Idaho. The fire burned in vegetation dominated by threetip sagebrush (Artemisia tripartita) and mountain big sagebrush (A. tridentata spp. vaseyana). Fire characteristics were not provided. Spiny phlox cover was 0.75% on unburned sites and 1.43% on burned sites. The relative density of spiny phlox seedlings was 0.004% from unburned soil and 0.006% from burned soil. The researcher indicated that spiny phlox recovered on burned sites primarily through vegetative means [1].
Spiny phlox did not emerge from soil collected from burned or unburned sites in sheep fescue-alpine bluegrass (Festuca ovina-Poa alpina), big sagebrush/Idaho fescue (A. tridentata/F. idahoensis), or bluebunch wheatgrass-Sandberg bluegrass-needle-and-thread grass (P. secunda-Hesperostipa comata) habitats in Yellowstone National Park, although it was present in the aboveground vegetation of all sites [28].
Germination: No information is available on this topic.
Seedling establishment/growth: Information on spiny phlox seedling establishment is limited. However, the following studies suggest that deep litter and/or dense shading restrict seedling establishment. Spiny phlox was restricted to interspaces in singleleaf pinyon-Utah juniper stands in Nevada [46]. Spiny phlox seedling density was 0.7/m² in 1984 and 1.4/m² in 1985 in a grazed bluebunch wheatgrass-blue grama range in Norris, Montana. Seedling densities were equal on the two study sites, although one was in poorer condition [27].
Vegetative regeneration: Spiny phlox regenerates vegetatively following fire or other aboveground damage and is common in early postfire communities [3,31,102]. Spiny phlox coverage was greater on 1-year-old burned sites than on unburned sites in Power County, southeastern Idaho, and regeneration was primarily vegetative [1].
Spiny phlox occurs in early and late seral communities and has been referred to as a pioneer, climax, and invading species [41,84,95]. Spiny phlox is tolerant of grazing and other relatively minor disturbances and is typical in early postfire communities.
Early seral: Spiny phlox is considered a pioneer species in dryland succession in south-central Utah's high plateaus. The spiny phlox root system tolerates fluctuating soil levels allowing it to occur on dunes formed when sand accumulates around crevice plants and along sandstone ledges [41]. Spiny phlox occurred on stabilized blowouts and stabilized dunes but was absent from unstabilized dunes in southern Saskatchewan. Unstabilized dunes were characterized by active erosion and/or deposition. Stabilized blowouts were round depressions that showed evidence of past erosion but no current erosion. Stabilized dunes showed no signs of recent erosion. The pH was higher, sand content greater, and organic matter lower on unstabilized dunes than on stabilized blowouts or dunes [66].
Late seral: A number of stable, late-seral, and/or climax communities provide spiny phlox habitat. In Glacier County, Montana, the prairie Junegrass-spiny phlox association is considered a "naturally occurring topoedaphic climax on moraine summits" [84]. In other parts of western Montana, spiny phlox is common in Idaho fescue-bluebunch wheatgrass communities that are considered late seral [75]. In southeastern Idaho's Craters of the Moon National Monument, Hood's phlox is a dominant forb in stable, undisturbed islands of low sagebrush/Idaho fescue-Thurber needlegrass (Achnatherum thurberianum) that were ungrazed, unburned and considered "pristine" [125].
Response to grazing: Many suggest that spiny phlox increases with domestic grazing or deteriorating range condition [68,78,83,95]; however, the grazing response is variable. For more information, see Other Management Considerations.
Response to other disturbances: Spiny phlox is typically present in early postfire communities [3,31,102] but is normally absent from severely disturbed mining areas.
Spiny phlox was present on windblown sites in threetip sagebrush vegetation in central Wyoming's Owl Creek range but was absent from mining test trenches dug almost 35 years earlier. The researcher noted that disturbed soil and/or snow pack levels may have affected spiny phlox's absence [50]. After studying disturbed and undisturbed sites in western Colorado's Piceance Basin where oil shale extraction occurs, researchers suggested that the loss of soil mycorrhizae may affect postdisturbance recovery. Spiny phlox, which has mycorrhizal associations, was absent from disturbed but present on undisturbed sites. Disturbed sites were abandoned roads that had been ripped to a depth of 18 inches (46 cm) three to four years prior to their study. Ninety-nine percent of the cover on undisturbed sites and less than 1% of the cover on disturbed sites was from species with mycorrhizal associations [105].
Degree of disturbance affected spiny phlox recovery in basin big sagebrush/mixed grass habitats in Colorado's Piceance Basin. Soil disturbance treatments were: 1) minimal disturbance to topsoil (A and B horizons), 2) "ripped" topsoil to 12-inch (30 cm) depths, 3) removal of top- and subsoil (A to C horizons) to 3 feet (1 m) that were mixed and then put back, 4) removal of top- and subsoil in 2 sections to 3 feet (1 m) that were replaced in reverse order. Spiny phlox was absent from sites treated with methods 3 and 4. Relative spiny phlox cover in successive years following disturbance treatments 1 and 2 are provided below [104].
Treatment 1 Treatment 2 Years since disturbance 1 4 5 6 1 4 5 6 Relative spiny phlox coverage (%) 6.34 3.81 5.92 8.33 1.14 1.44 3.74 7.52
Phlox hoodii, the spiny phlox or carpet phlox, is a species of phlox. It is a plant of western North America, where it is a common flower in sagebrush country, mostly growing in dry lithosol habitats.[1] It is among the first plants to bloom in spring, after the snow has melted. Its distribution extends from Alaska to Arizona.[2] There are many subspecies.
This perennial herb is variable in morphology, but usually forms a tight mat or loose clump on the ground.[2] The short stems emerge from a woody taproot and caudex unit and the plant form is no more than 13 centimetres (5 in) tall.[2] The abundant tiny, sharp-pointed leaves are oppositely arranged and barely exceed one centimetre (1⁄3 in) long. The herbage is hairy in texture, the hairs short to long, woolly to cobwebby.[2] The appearance of the plant is almost mosslike until blooming.[3] The inflorescence is a solitary flower in shades of white, pink, or blue.[2] It has a tubular throat about one centimetre (1⁄3 in) long spreading into a flat five-lobed corolla.
Phlox hoodii, the spiny phlox or carpet phlox, is a species of phlox. It is a plant of western North America, where it is a common flower in sagebrush country, mostly growing in dry lithosol habitats. It is among the first plants to bloom in spring, after the snow has melted. Its distribution extends from Alaska to Arizona. There are many subspecies.
This perennial herb is variable in morphology, but usually forms a tight mat or loose clump on the ground. The short stems emerge from a woody taproot and caudex unit and the plant form is no more than 13 centimetres (5 in) tall. The abundant tiny, sharp-pointed leaves are oppositely arranged and barely exceed one centimetre (1⁄3 in) long. The herbage is hairy in texture, the hairs short to long, woolly to cobwebby. The appearance of the plant is almost mosslike until blooming. The inflorescence is a solitary flower in shades of white, pink, or blue. It has a tubular throat about one centimetre (1⁄3 in) long spreading into a flat five-lobed corolla.
