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Results tagged “polemoniaceae”

Apr 26, 2013: Linanthus dichotomus

The Traverse Creek Botanical Special Interest Area was established to protect a community of plants associated with the serpentine soils of the locale. Serpentine soils have high concentrations of metals like magnesium, nickel and chromium which few plant species can tolerate; these metals have an effect on soil chemistry and mineral availability. Species that do tolerate serpentine are often ecological specialists, adapted or evolved for serpentine environments.

Traverse Creek is ideal for photographers interested in both botany and time-lapse imagery. Lewisia rediviva, which is tolerant of serpentine soils and present here in quantity, will only open during the mid-day sun. Time-lapse imagery of the flowers opening and closing is possible from mid-morning to late afternoon. Conversely, the flowers of most plants of today's species are closed during the same time period. They only begin to open in the late afternoon, and then the flowers persist through the night and early morning. This is somewhat evident in my photographs, as the first image (with only one flower fully open in the mid-bottom centre) is from when I arrived on-site, and the third image is from when I left.

This species is Linanthus dichotomus, commonly known as evening-snow (Calphotos link, with more images). An annual species, it can sometimes be seen in dense stands when conditions are right, such as timely and sufficient rainfall (I believe this can occur at the Traverse Creek site, but not this year).

I should point out that the Jepson eFlora recognizes two subspecies of Linanthus dichotomus: subspecies dichotomus, which has the evening-open (or vespertine) behaviour, and Linanthus dichotomus subsp. meridanius, which has a daytime-open behaviour. Likely, this decision was in part based on the strength of the evidence from this paper: Chess, SK et al. 2008. Geographic divergence in floral morphology and scent in Linanthus dichotomus (Polemoniaceae). Am. J. Bot. 95(12):1652-9. doi: 10.3732/ajb.0800118. The scientists discovered significant differences between the scents of the two subspecies (by measuring the type and quantity of the floral volatile compounds). Compounds that typically attract nighttime moths were found in high concentrations in Linanthus dichotomus subsp. dichotomus, while Linanthus dichotomus subsp. meridanius had a suite of compounds more typically associated with attracting generalist daytime pollinators.

The El Dorado chapter of the California Native Plant Society shares more information about the Traverse Creek Botanical Special Interest Area.

Apr 3, 2013: Ipomopsis havardii

Ipomopsis havardii

A thanks to first-time contributor Gary Nored (aka AnEyeForTexas@Flickr) for today's photograph of Ipomopsis havardii. Gary shared this image via the Botany Photo of the Day Flickr Pool. Gary has another photograph of the species here: Ipomopsis havardii. Much appreciated!

Havard's ipomopsis is endemic to a small area of the Chihuahuan Desert. This species is only found in southwest Texas and the state of Chihuahua in northwest Mexico. A.M. Powell's Trees & Shrubs of the Trans-Pecos and Adjacent Areas describes this subshrub / herbaceous perennial as occurring at elevations of 750m (2500 ft.) to 1200m (4000 ft.), on "slopes of desertic mountains and hills".

About 30 species of Ipomopsis are recognized, all in the New World. The genus has a disjunct distribution of western North America, southeast USA and southern South America.

Dec 1, 2011: Phlox diffusa

Spreading phlox is common within its range, though typically reliable resources suggest different ranges. USDA GRIN has a more restricted western range for Phlox diffusa than USDA PLANTS database; the latter suggests Phlox diffusa ranges across much of western North America, going as far east as South Dakota and into New Mexico. This suggests some taxonomic confusion, and this is borne out by some floras recognizing multiple subspecies and varieties within Phlox diffusa, and others using the term "highly variable".

According to some references, today's plants could also be recognized as Phlox diffusa subsp. longistylis, differing from Phlox diffusa subsp. diffusa in having larger corolla lobes (8-10mm long instead of under 8mm in one reference, 5-9mm in another) that are nearly as wide as long (instead of twice as long as wide) and styles 5-6mm long (instead of 2-4mm). However, one reference also notes that some plants do not cleanly fit into either subspecies (i.e., through a mixture of characters such as short styles but large corolla lobes), explaining that this is why some botanists choose to recognize only a single variable species. This would be my inclination in this case.

Flower colour is another variable characteristic. In my experience, pink to lavender is far more common, but Phlox diffusa is one of the easiest species to find white-flowered individuals. While the relative proportion of white to pink individuals is certainly a factor, the task is also made easier by the showiness of these mat-growing plants and the general lack of "colour competition" where they grow. Simply, few other flowering plants inhabit the same niche (mesic to dry rocky slopes and rock outcrops), so the spreading phlox tends to stand out. White-flowered variants is another BPotD series I could do, I suppose, as I suspect I have about 20 species photographed with the typical coloured flower and the white variant. Or, perhaps another half-decade of flower photography will yield a presentation on the topic.

Additional photographs of this species, including the range of flower colour variation, are available from the Burke Museum: Phlox diffusa.

Apr 4, 2011: Eriastrum densifolium subsp. sanctorum

Eriastrum densifolium subsp. sanctorum

Claire Fadul wrote today's entry:

Dale Hameister (Dale Hameister@Flickr) of Redlands, CA provided us with this vibrant photograph of Eriastrum densifolium subsp. sanctorum (taken in early June last year) via the Botany Photo of the Day Flickr Pool. Much appreciated Dale!

Eriastrum densifolium, or giant woollystar, (this particular sub-species is the rarer Santa Ana woollystar) is a common sight in the drier places of California and can usually be found in sandy soils and seasonally dry washes. California is the centre of present-day biodiversity for the Polemoniaceae, or phlox family. Nowadays, the family is mostly found in the New World (approx. 25 genera containing 400 species in North and South America vs. only 3 genera in the Old World). However, what few fossil records exist (Polemoniaceae tend not to grow in places conducive to fossil formation) indicate the presence of Polemoniaceae pollen from Eocene Spain and Pliocene Europe (as well as Miocene California and mid-Eocene Utah).

Eriastrum densifolium subsp. sanctorum is both endemic and endangered in southern California, where it inhabits alluvial washes around the Santa Ana River floodplain. The Seven Oaks Dam is a major threat to the long-term survival of Eriastrum densifolium subsp. sanctorum, as it reduces crucial sediment and new sand deposits the plant relies on for reproduction. Fortunately, a number of people, including professors and students at Cal State Fullerton, are conducting long-term research with an eye to conservation of this rare taxon.

Blooming in the summertime, Eriastrum densifolium subsp. sanctorum has particular pollinators which also share the same habitat requirements of sandy washes. Depending on the location, Burk et al. in a 1989 field study found digger bees, anise swallowtail butterfly, and various hummingbirds to be common pollinators, as well as the "giant flower-loving fly", Raphiomidas actoni subsp. actoni. Some of these species may be mutually dependent on the Santa Ana woollystar, so it is important to continue conservation efforts for the endangered woollystar in order to preserve all constituents of this fragile ecosystem.

Feb 25, 2011: Polemonium boreale

Polemonium boreale

Last night, I attended Ron Long's extended presentation on "Pink Mountain Revisited -- The Conservation Crisis That No One Is Aware Of". For local readers of BPotD, Ron will be giving a shorter version of the lecture on Monday at noon here at the Garden. I encourage you to attend to get informed about the industrial threats to this special area.

I visited Pink Mountain last year in mid-June with Ron. The species in today's photograph, northern Jacob's-ladder, is one of ten British Columbian blue-listed species (and one-red listed) of vascular plants identified to-date from Pink Mountain. It is my understanding that no site identified as-yet north of the 50th parallel in British Columbia has as many threatened and endangered species in so small an area (the border with the US on mainland British Columbia is the 49th parallel). This area, though, is a candidate for a wind farm -- meaning (in part) widening and improvement of roads to transport the materials and concrete needed to create the concrete slabs for supporting the turbines. Ron remained in the area for weeks after I had to return to work, and witnessed a construction crew (there to re-install a wind-speed test tower) decimate (in the literal sense) a population of blue-listed Ranunculus pedatifidus subsp. affinis through the parking of heavy equipment.

Road improvement and widening is a direct threat to the populations of Polemonium boreale on Pink Mountain, as very few (any?) individuals can be found more than 5m (16ft.) distant from the edge of the road. Unfortunately, the road typically follows the highest ridge where the soil layer is at its thinnest and where Polemonium boreale thrives in the gravelly substrate.

Despite its rarity in British Columbia, Polemonium boreale is stable as a species world-wide, with a panarctic distribution (Canada, Alaska, Russia, Greenland and Norway), including Svalbard: Polemonium boreale.

Polemonium boreale is a low-growing perennial, perhaps reaching 30cm tall. If I recall correctly, a quick way to tell it apart from the nearby Polemonium acutiflorum when not in flower was that the foliage did not have a skunky smell if the leaves were lightly pressed between one's fingers (or perhaps it was the other way around). When in flower, the tips of the corolla lobes of Polemonium boreale are rounded with more apparent colour venation on the surface than those of the pointy-tipped Polemonium acutiflorum.

Additional photographs are available from the Toolik-Arctic Geobotanical Atlas: Polemonium boreale.


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