Tom Schweich  

2014

Thursday, March 6th

Slides in PDF format are available here: Flora of the Mono Lake basin.

Friday, March 7th

Saturday, 2 August 2014

Green Mountain, Jefferson County, Colorado. Rooney Valley Trail, west side of Green Mountain. 39.6917°N, 105.176°W. WGS 1984. Elev. 1912 m. Small patch beside swale.

Woody perennial to 50 cm., forming dense colonies in moist open swales, [spreading by long sparsely-branched rhizomes,] Twigs without lenticels, minutely hairy when young; Leaves opposite, ovate, to 7 cm. × 5 cm. wide, reduced above, thick, approaching leathery, pinnately veined, upper surface glabrous, lower few short white hairs, margin slightly wavy, slightly rolled under, sparsely curved hairy; Petioles to 7 mm.; Inflorescence axillary (and terminal?); Floral bracts triangular, 3 mm.; Flowers in dense axillary clusters, bisexual, ±radial, possibly slightly bilateral, 2 or more whorls; Corolla fused at base, tube 2 mm., throat with recurved hairs, lobes 5, 2-3 mm, slightly longer than tube, white with magenta mottling; Stamens 5, alternate, exserted; Anthers versatile; Ovary inferior; Pistil 1; Style exserted; Stigma entire; Fruit a berry, green when young, mature color and size unknown (Described from specimen seen on Green Mountain, 2 August 2014).

Sunday, August 10th

Tucker Gulch (lower), Jefferson County, Colorado. Common within the city limits of Golden, along the creek of Tucker Gulch and the Tucker Gulch Trail, about 250 m. north of the First Street Bridge, and 350 m. south southwest of Ford Street. 39.7687°N, 105.2283°W. WGS 1984. Elev. 1777 m. Common, low-growing subshrub with yellow flowers.

Perennial herb, to 50 cm.; Stem, moderately strigose, proximally eglandular, distally hairy and glandular, but generally hairs exceed glands, Leaves, cauline alternate, well-distributed along stem, 16 mm. × 7 mm. wide, elliptic to obovate, entire, some margins contorted after drying, 1-veined, distal perpendicular to stems, not densely canescent, generally hairs > glands; Inflorescence heads 1-8 per stem, terminating leafy stems, not subtended by leafy bracts; Heads solitary, with both ray and disk flowers; Phyllaries in 2+ series, unequal, to 7 mm.; Rays, 9 mm.; Pappus double, outer narrow scales ≤ 1 mm. (easier to see on mature fruit), inner bristles, 6.5 mm., white; Fruit, disk 3 mm., hairy.

Tucker Gulch (lower), Jefferson County, Colorado. 39.7687°N, 105.2283°W. WGS 1984. Elev. 1777 m. Common, white-flowered plant in mowed and unmowed sunny areas all along the trail.

Annual terrestrial herb, to 50 cm.; Leaves, cauline, elliptical, 20 mm. × 5 mm.; Flowers, not bracteate; Petals, 4, white, deeply bilobed; Style, 1.4 mm. in young fruit; Fruit, elliptical, 7 mm. × 4 mm. wide × 2 mm. thick, flattened parallel to papery internal partition.

Monday, August 11th

Wednesday, August 13th

Friday, August 15th

Sunday, August 17th

Field Trip Stop 15 — North Table Mountain Rockfall Area — of Noe, et al. (1999) forms in the parking lot of the Hillside Community Church at 103 N. Ford Street.

The rockfall and landslide hazard area around North Table Mountain was mapped by the U.S. Geological Survey during the 1970s (Simpson, 1973a; 1973b). Jefferson County has adopted the mapped hazard area as part of its geologic-hazards overlay, and has considered it to be a “no-build” area. This was challenged in the 1980s by a developer, who staged an actual rock-rolling demonstration on the northwest flank of the mountain in order to prove the fallacy of the outer (distal) hazard-area boundaries. The demonstration was curtailed (and the subdivision application was subsequently denied) after several boulders rolled beyond the outer boundary, but not before one boulder had bounced at least 10 feet (3 m) into the air and knocked a cross-bar off a high-tension power-line tower at the base of the mountain.

The rockfall hazard area, as mapped by the USGS, exists in both unincorporated Jefferson County and the incorporated city of Golden. Unfortunately, protection of the public from the rockfall hazard does appear to stop at the jurisdictional boundary in this case. The houses we see on the hillside above are located within the city of Golden, which has not adopted Simpson’s map. This subdivision was approved and has expanded due the absence of any requirements for home-rule cities to follow the state-mandated, geologic-hazard review process for subdivisions.

Looking to the north and south, we can see the distinctive hogback of the Dakota Sandstone at both ends of the valley. But why is this hogback missing at the valley center? The answer is that the Golden Fault, a large, Laramide thrust fault, weaves along the valley just to the east of the mountain front. Here, the fault has displaced nearly 8,000 feet of the Paleozoic and Mesozoic, sedimentary section (Van Horn, 1976). The trace of the fault can be seen as it cuts up the side of the first large alluvial terrace to the south of Clear Creek. There is a distinct break in the vegetation between the Fountain Formation to the west (covered with mountain mahogany shrubs) and the Pierre Shale to the east (covered with grasses).

Looking directly west, we see a road cut for State Highway 93. This portion of the highway was first constructed in 1991. A small landslide formed in the west (opposite) face of the cut shortly thereafter, and the resulting toe bulge closed the southbound lanes of the new highway. Within a year, the landslide had developed a rim of head scarps with up to 12 feet of vertical slippage, and had captured the surface flow of a small stream in Magpie Gulch. Early efforts to drain the landslide were unsuccessful. A full geologic investigation subsequently revealed that the landslide sits directly atop the Golden Fault, with low-permeability Pierre Shale on the eastern side and a wedge of fractured, permeable Fountain Formation on the western side. In 1994, three lines of rock anchors (about 40 anchors in total) were installed across the landslide. The Magpie Gulch stream was piped across the head scarps, longer horizontal drains were installed, and a remote data-logging unit was set up. To date, this mitigative effort appears to have been successful. The combined maintenance and mitigation operations for this incident are reported to have cost about 3 million dollars.

The houses to the north of the landslide were built shortly after the landslide was mitigated and all signs of its existence had been “erased” from view. One can only imagine the concern of these residents had the landslide been active a few years later. This is a good illustration of the often short-term public memory of geologic hazards.

Golden, Jefferson County, Colorado. Waste places, alley between Arapahoe Street and Cheyenne St, north of 5th Street. 36.7611°N, 105.2291°W. WGS 1984. Elev. 1759 m. Small colony between fence and pavement.

Coll. No. 1057, 18 Aug 2014: Terrestrial green perennial herb, to 60 cm.; Stem ascending, little branched; Sap milky; Leaves, cauline, alternate, ovate, 7 cm. × 4 cm.; Petioles 10 mm.; Inflorescence, flowers 1-2 in axils; Pedicels to 12 mm.; Perianth in 2+ whorls; Corolla, radial, bell-shaped, regular; Petals united; Ovary inferior; Seeds (unknown).

Golden, Jefferson County, Colorado. Arapahoe Street, between 4th and 5th. 39.7612°N, 105.2285°W. WGS 1984. Elev. 1758 m. Occasional weed of landscaped areas.

Coll. No. 1058, 18 Aug 2014: Annual/perennial unknown, probably perennial in 1st year; Culm, lacking short rhizome; Sheath, conspicuous tufts of hairs at proximal end, Ackerfield (2015) says &lqquo;... tufts of hair at the tips ...&rdquo, sparsely hairy at summit (distal end); Leaf, elongate, erect, blade rolled in bud; Panicle, large, 17 cm., open, lower nodes few branches, not appearing whorled, branches spreading at maturity, branches 2-7 cm.; Pedicels 2.0-4.5 mm.; Spikelets, not crowded, 2.8 mm., Glumes 1.5 & 2.5 mm.

Discarded. Pretty much destroyed while looking at arrangement of panicle branches at base of inflorescence.

Golden, Jefferson County, Colorado. South side of Magpie Gulch east of CO Highway 93. 39.7639°N, 105.2347°W. WGS 1984. Elev. 1768 m.

Coll. No. 1059, 28 Aug 2014: Perennial herb, of eastern slope, to 50 cm.; Leaves alternate, to 12 cm. × 2 cm. wide; margin shallowly toothed; Bracts, 15 mm., pinnately toothed, some basal and some clearly arising from the capsule; Petals, 10+, 40 mm. × 7 mm. wide; Stamens many; Filaments broad, narrowing at distal end; Anthers basifixed; Capsule, 30 mm. × 10 mm. diameter, erect, not curved at base, thick cylindric; Calyx (in fruit), lobes 9-12 mm.; Seeds, horizontal in capsule and winged, 3.8 mm. × 2.5 mm. wide, wing width 0.5-0.8 mm.

Typically, M. nuda is described as having “1 or 2 bracts usually at base” of capsule (Harrington, 1954), or “bracts not fused to ovary wall” (Weber & Wittmann, 2012), or “bracts free from capsule” (Ackerfield, 2015). However, this collection clearly has 15 mm. pinnatifid bracts arising from the capsule. Such character would lead to M. decapetala. Regardless, the small size of those bracts, and small size of other characters support placing this in M. nuda rather than M. decapetala.

Andropogon gerardii Vitman. Big Bluestem.

Golden, Jefferson County, Colorado. Transition between high plains and Front Range, 1.8 km northwest of the GNIS location of Golden, on the Nightbird Gulch trail, 290 m. from the trailhead on Canyon Point Circle. 39.7638°N, 105.2392°W. WGS 1984. Elev. 1849 m

Coll. No. 1060, 28 Aug 2014, characters observed: Perennial, to 85 cm., clumped, rhizomes unknown; Leaves, blade and sheath differentiated; Sheath, 11 cm., open; Ligule, membraneous (though surrounded by hairs), 3 mm., auricles 0; Blade, soft, flat, 27 cm., hairy near ligule; Inflorescence, 80 mm., > leaves, 1-2 per stem, in 5-6 digitate branches, spikelets many; Rachis, soft bristles on margins and at nodes; Disarticulation at nodes of rachis; Spikelets in pairs, Sterile spikelet, 7 mm., pedicel 4.5 mm.; Fertile spikelet, Florets #1, Glumes, awns 0, ±equal, lower keeled, upper flattened and grooved; Lemma, 6 mm., membraneous, rolled, glabrous, tip 2-forked, awn, #1, 13 mm., bent, twisted, attached on back; Stamens, 3; Anthers, yellow; Ovary, glabrous; Stigma, feathery.

Golden, Jefferson County, Colorado. Illinois Street at alley between 4th and 5th Streets. 39.7602°N, 105.2308°W. WGS 1984 Elev. 1763 m.

Collection No. 1063, 17 September 2014, characters observed: Perennial shrub, woody at base, to 1 m., sprawling to erect; Stem covered with felt-like tomentum (long hairs infiltrated with resin, must scrape with knife to expose); Leaves, alternate, lance-linear, 70 mm. × 3 mm., not twisted in the manner of some related species, upper surface tomentose, margin entire; Heads discoid (with only disk flowers), cymose at ends of branches, narrowly tubular; Involucre 8 mm., not spiny; Phyllaries in 3 vertical ranks, outer << inner, keeled, some with few short hairs; Receptacles not chaffy, but have some short (<0.5 mm.) appendages between flowers; Flowers #5; Corolla tube (i.e., petals united at base) 7.5 mm. + lobes #5, 1 mm., glabrous throughout; Ovary inferior; Pappus of bristles, 6-7 mm., white; Stamens 5; Anthers connate (united), 2 mm., acute at base; Style 11 mm., branches half-round in cross-section, stigmatic 1 mm. + appendage 2 mm., glabrous inside, uniformly short hairy on outside, tips rounded; cypselae, all similar in shape, 5 mm., short hairy;

Not known from California. In Ackerfield (2012), Asteraceae, Key 2, 15a-b, a question of how tomentose the stems and leaves are made keying tricky.

Golden, Jefferson County, Colorado. Waste place at 4th and Illinois Streets, against the school yard fence. 39.7607°N, 105.2312°W. WGS 1984. Elev. 1773 m.

Collection No. 1063, 17 September 2014, characters observed: Perennial shrub, woody at base, to 1 m., sprawling to erect; Stem covered with felt-like tomentum (long hairs infiltrated with resin, must scrape with knife to expose); Leaves, alternate, lance-linear, 70 mm. × 3 mm., not twisted in the manner of some related species, upper surface tomentose, margin entire; Heads discoid (with only disk flowers), cymose at ends of branches, narrowly tubular; Involucre 8 mm., not spiny; Phyllaries in 3 vertical ranks, outer << inner, keeled, some with few short hairs; Receptacles not chaffy, but have some short (<0.5 mm.) appendages between flowers; Flowers #5; Corolla tube (i.e., petals united at base) 7.5 mm. + lobes #5, 1 mm., glabrous throughout; Ovary inferior; Pappus of bristles, 6-7 mm., white; Stamens 5; Anthers connate (united), 2 mm., acute at base; Style 11 mm., branches half-round in cross-section, stigmatic 1 mm. + appendage 2 mm., glabrous inside, uniformly short hairy on outside, tips rounded; cypselae, all similar in shape, 5 mm., short hairy;

Not known from California. In Ackerfield (2012), Asteraceae, Key 2, 15a-b, a question of how tomentose the stems and leaves are made keying tricky.

Sunday, 21 September

Tuesday, 23 September

Wednesday, 24 September

Blepharoneuron tricholepis (Torr.) Nash. Pine Dropseed.

Unknown, Douglas County, Colorado. Lower montane ponderosa pine, gravely soil derived from Pikes Peak granite.

Coll. No. 1065, 18 Sep 2014, characters observed: Perennial bunchgrass to 35 cm.; Sheath open; Ligule membraneous; Inflorescence 1-2, loose panicle, 15 cm. long × 1.5 cm. wide, >leaves; Axis scabrous; Spikelets, many, similar, >2 per node, 1-flowered, 2 mm.; Florets, 1 per spikelet, bisexual; Glumes, lower 2.0 mm., upper 2.5 mm., awns 0; Lemma, 2.5 mm., keeled, veins 3, densely hairy, awns 0; Palea, <lemma, keel hairy, margin glabrous.

Friday, 3 October

Monday, October 6th

Cressmans Gulch (lower), Jefferson County, Colorado. Many plants in and around the surge basin north of Wyoming Street at Ridge Road. 39.7753°N, 105.2303°W. Elev. 1810 m. Upright shrub with yellow flowers and large reddish seed pods.

Collection No. 1066, 6 October 2014, characters observed: Perennial shrub, to 2 m., woody below; Stem erect, unarmed; Leaves compound, odd-pinnate (with terminal leaflet); Leaflets, 11, 16 mm. × 12 mm. wide, notched at tip, glabrous above, sparsely appressed hairy below; Inflorescence a raceme, axillary, 9± flowers; Calyx, 5-merous, 5 mm. × 6 mm. dia., appressed hairy; Flowers, 19 mm., yellow, with dark markings; Banner, 10 mm.; Wings, 10 mm. × 4 mm., reduced in comparison to Lupinus; Keel, fully enclosing stamens and pistil, glabrous; Stamens, 10; Filaments, 9 fused, 1 free; Style, recurved; Fruit, inflated, bladder-like, 50 mm. × 22 mm., walls papery, color reddish fading to brown, base stalk-like; Seeds, reniform, flattened, 6 mm. × 4 mm. × 2 mm., brown, surface smooth; native to southern Europe.

Weber & Wittmann (2012) note “… introduced about 1913 around houses in Sunshine Canyon northwest of Boulder, now spreading and becoming estabished in the foothill canyons …”

Wednesday, 8 October

North Table Mountain, Jefferson County, Colorado. Near the south rim. 39.7753°N, 105.2303°W. Elev. 1950 m. Rocky slope with little soil development near rim of mesa, growing with Brickellia californica(?).

Coll. No. 1067, 8 Oct 2014, characters observed while keying: Perennial herb, to 30 cm., woody at base; Stems many; Leaves alternate, 9 mm., pinnately dissected into 7 parts, silvery hairy; Inflorescence raceme-like, indeterminate, heads 1-3 in axils; Heads have only disk flowers, all alike; Involucre of hairy phyllaries; Phyllaries in 2 series, hairy, not gummy or with tips recurved; Receptacle hairy, not chaffy or bristly; Flowers fertile; Pappus absent; growing with Brickellia californica(?).

North Table Mountain, Jefferson County, Colorado. Near the south rim. 39.7687°N, 105.2156°W. Elev. 1950 m. Rocky slope with little soil development near rim of mesa.

Coll. No. 1068, 8 Oct 2014, characters observed while keying: Perennial herb, to 40 cm., woody at base; Leaves opposite below, alternate above, 50 mm. × 22 mm., ovate, pinnately divided; Inflorescence indeterminate, appearing raceme-like, 2 kinds of flowers, pistillate heads many, distal, carpellate heads few, clustered in distal leafy axils; Phyllaries fused into a cup; Receptacle not chaffy; Pappus absent.

Wednesday, October 15th

South Table Mountain, Jefferson County, Colorado. West side of South Table Mountain, along south loop of Lubahn Trail. 39.7523°N, 105.2081°W. Elev. 1835 m. Good example of carpellate flowers.

Friday October 24th.

Saturday, 25 October

Thursday, October 30th

Saturday, November 1st

Sunday, November 9th

Saturday, November 22nd

Wednesday, November 26th

Saturday, November 29th

Monday, December 7th

Thursday, December 11th

Monday, December 15th

Saturday, December 20th

Sunday, December 21st