Home / Resources and Writings / Botany Photo of the Day
Botany Photo of the Day
In science, beauty. In beauty, science. Daily.
February 8, 2010
Pandanus tectorius
Thank you to my colleague, Eric La Fountaine, for providing both today's photograph and write-up. Eric writes:
Pandanus tectorius is a very common sight on the Hawaiian islands. It is found in tropical Asia, Australia and on many Pacific Islands. It is generally thought to be indigenous to Hawaii, but additional varieties may have been brought by Polynesian explorers. It is sometimes given the amusing moniker, tourist pineapple, and I must admit I heard the words, "oh look--pineapples", from tourists looking at the plant. The background of the photo shows the dramatic topography of the Nā Pali Coast. By my estimation, the verdant peaks in this view rise around 250 metres (800 ft).
The shrubs or small trees are variable, generally growing 4-14 metres (13-46 ft) tall with similar dimensions of canopy spread. Pandanus tectorius is dioecious, i.e., male and female flowers appear on separate plants. The single trunk of the plant reaches a height of around 4 metres before branching. It is supported by a dense skirt of prop roots at its base. Long strap-like leaves are spirally arranged. As the plant grows in height, lower leaves fall off. Due to the spiral arrangement of the leaves, the now-bare trunk is left with a twisted appearance, leading to another common name, screwpine.
Pandanus tectorius is one of the most important plant resources to Pacific Island peoples. The species is used extensively for weaving, food and medicine, craft making, ornament, dye and other purposes. Both the seeds and fruit are eaten. Many varieties of the plant have been selected to best serve these cultural needs. Some provide better tasting fruit, others are more suitable for weaving.
Two pages of photos showing many aspects of the tree can be seen on Plants of Hawaii. To learn more, excellent articles describe the species at the Culture Sheet and at Pacific Island Agroforestry (PDF 1.82MB).
Posted by Daniel Mosquin at 12:00 AM | Comments (13)
February 5, 2010
Gentiana prostrata
The Gentianaceae series is concluded with two photographs taken by local plant guru Alan Tracey (thank you!). They are photographs of the same species of gentian, but from locations over 12 000km (7000miles) apart. The image with many flowers was taken in La Parva, Chile, while the solitary flower was photographed somewhere along the Dempster Highway in the Northwest Territories of Canada.
Gentiana prostrata, or pygmy gentian, is a low-growing 3-7cm (to 3in.) tall annual. Its preferred habitat is wet meadows of high altitudes or tundra. Conflicting accounts of its range abound; the Flora of China account does not mention South America, nor does The Jepson Manual. Though both of these cite Eurasia and western North America, the absence of South America is curious. The species, after all, was collected by Darwin near the Straits of Magellan during the Voyage of The Beagle. Perhaps it is because the species was thought to have been dispersed to South America by albatross (might be a subscription-only link)?
Gentiana prostrata was scientifically described by the Bohemian-born botanist, Tadeáš Haenke. To read more about Haenke, an excellent compilation of articles about his life are presented in the Botanical Electronic News, Issues 287 and 288.
Posted by Daniel Mosquin at 11:00 AM | Comments (12)
February 4, 2010
Gentianella hirculus
The second last entry in the series on Gentianaceae takes us to the Páramo of southern Ecuador, a high-altitude grassland ecosystem dominated by bunch-grasses. Another big thank you to Eric in SF@Flickr for sharing his photographs (original image | Botany Photo of the Day Flickr Pool).
The question was asked by Mary Hamilton in the comment section to Gentiana calycosa as to whether one of the "closed gentians" (that can be seen in New Jersey) would be featured. Mary was probably thinking of Gentiana andrewsii (see more photos), but there are other "closed" gentians and gentian relatives, including Gentianella quinquefolia and today's species, Gentianella hirculus.
Gentianella means "dwarf gentian" -- today's species reaches only 10cm (4in.) tall. The centre of diversity for the genus is South America, though the two hundred plus species are distributed throughout most temperate regions of the world. Gentianella hirculus is considered endangered by the IUCN Red List, with only 12 populations of plants remaining in the wild. Threats include grazing and, paradoxically, visitors to the park where most (all?) plants reside.
"Closed" gentians are either known or assumed to be pollinated by long-tongued bees (example). Take that, Gene Simmons.
Posted by Daniel Mosquin at 1:00 PM | Comments (12)
February 3, 2010
Frasera albicaulis
My last photographs for the series on the Gentianaceae today, though the series will continue until Friday.
These images were taken in mid-July 2009 northeast of the Lick Creek Campground in northeast Oregon, part of the USA's Hells Canyon National Recreation Area. I believe this particular plant was spotted by my traveling companion, and I was quite delighted to see it in person, as I had only known it from books previously.
A close relative of Frasera speciosa, white-stemmed (= albicaulis) frasera occupies a different habitat. Where Frasera speciosa is a species typically found in moist alpine or subalpine meadows, the much shorter (to 75cm / 30in) Frasera albicaulis tends to be a species of dry, open sites (including sagebrush-steppe). In this case, it was growing roadside in an open area heavily dotted with pieces of gravel with a low-growing species of Allium (the purple spots in the background of the second photograph).
While I was intrigued most by the unusual colours of its flowers, others have been more interested in its roots. A 1968 paper by Stout et al. in Tetrahedron explains the investigation of the roots for the presence of xanthones: Xanthones of the Gentianaceae--II *1: Frasera albicaulis Dougl. ex Griesb.. While many xanthones (i.e., molecules using xanthone as a central core molecule) were and are produced synthetically, fifteen different kinds were found in the roots of Frasera albicaulis -- ten of which had previously not been known to occur in nature. Xanthone proper is used in the production of insecticides, while some of the synthetic xanthones are involved in the manufacture of UV-resistant films.
Frasera albicaulis is native to western North America. For more photographs and a description of the species, see the Burke Museum's page: Frasera albicaulis.
Posted by Daniel Mosquin at 2:00 PM | Comments (11)
February 2, 2010
Gentianopsis detonsa
Within the Gentianaceae, taxa within the genus Gentianopsis are collectively known as the fringed gentians. Depending on the classification scheme used, there are somewhere between 16 and 25 species of Gentianopsis, broadly distributed in north temperate regions. Gentianopsis detonsa is known commonly as the windmill fringed gentian (a phenomenon better seen here: fringed gentian at Yellowstone National Park).
This little annual or biennial, growing from 5cm to 60cm (to 2ft.) high, is recognized by J.M. Gillett as being a subspecies of Gentianopsis detonsa, i.e., Gentiana detonsa (Rottb.) Ma subsp. yukonensis (J.M. Gillett) J.M. Gillett (as noted in William J. Cody's encyclopedia Flora of the Yukon Territory. If one accepts this subspecies as being valid (and few other references do), then this is a taxon that is "endemic to the valley of the Yukon River and its tributaries in central Alaska and southwestern Yukon Territory", where it grows in "forest meadows and subalpine heathland". It's also noted that it grows in disturbed situations. Accordingly, this particular plant was photographed along the highway northwest of Haines Junction, in a small roadside meadow ringed by trees that had (at some point in the past) been disturbed by bush roads.
On the other hand, if one doesn't recognize this as a subspecies only found in Yukon and Alaska, then it is folded into a species with a much wider distribution: at the least, much of northern North America--and sometimes more, including south through the Rockies into Utah, New Mexico and Nevada. In addition to North America, the species is also found in Iceland, Norway and Russia.
I am partial to fringed gentians as they are one of the first plants I could recognize that weren't "always there" (and by that I mean they weren't a tree or shrub). It was a special trip to go with my mother once every year or two (sometimes we missed them) to see the small patch of fringed gentians that grew in the ditch a few kilometres from my home.
Posted by Daniel Mosquin at 1:00 PM | Comments (5)
February 1, 2010
Gentiana calycosa
Continuing with the series on the gentian family, Gentiana calycosa is a true gentian, commonly known as mountain bog gentian, mountain gentian, explorer's gentian or Rainier pleated gentian. This photograph was taken in early August on the flanks of Mt. Adams, Washington, in the same area as these images of Gentiana calycosa.
The common name Rainier pleated gentian hints at a western North American distribution, and that is indeed the case, with a range from British Columbia to California and east to western Wyoming (as an aside, I know some of you get impatient with photographs from western North America, but it's what I have on hand--there'll be at least one photograph from elsewhere in the world later in the series). Other common names, as you might surmise, rightly suggest it is a species of subalpine and alpine environments along streams, wet meadows and bogs.
The epithet calycosa means "full calyx", and I'm afraid I don't know why that is noteworthy in comparison to other gentians.
Cultivation of Gentiana calycosa is possible, but according to the Encyclopedia of Northwest Native Plants for Gardens and Landscapes, it is "a perennial for the determined, patient gardener". This is due to its preference for moist, yet well-drained soils--in other words, trying to replicate a mountain environment with a cool stream or seep.
Posted by Daniel Mosquin at 1:00 PM | Comments (11)
January 29, 2010
Frasera speciosa
In comparison to yesterday's Zeltnera muehlenbergii, Frasera speciosa is a giant. Individuals can reach heights of 2.5m (8ft), whereas yesterday's species occasionally reaches 1m, but is often much shorter. There is an age difference, too. Zeltnera muehlenbergii has an annual life-cycle, meaning the individual plants germinate, grow, flower, fruit and die within the span of one year. Frasera speciosa is much different. Once thought to be a biennial (having a two-year life-cycle), David Inouye and Orley R. Taylor Jr. demonstrated that this species is actually a perennial, having a life span that can extend past sixty years (in Oecologia 47(2): 171-174, from January 1980: Variation in Generation Time in Frasera speciosa (Gentianaceae), a Long-lived Perennial Monocarp).
Another intriguing fact one can glean from their paper is that Frasera speciosa is monocarpic, meaning it flowers and fruits in only the last year of its life, spending the remaining decades and years as a mass of leaves. With a range of age before flowering, (minimum age roughly 20 years), how do individual plants ensure cross-pollination? Taylor and Inouye published a subsequent Ecology paper on this topic in 1985, Sychrony and Periodicity of Flowering in Frasera speciosa (Gentianaceae). In short, mature individuals within a population will synchronize flowering in 2-4 year intervals, so that there are peak years (to the extent of >90% of the mature individuals flowering) and low years. What prompts the synchronization is not detailed in these papers, but in some instances, the evidence suggests environmental factors.
One last point: why is it important to know the life-cycle of a plant? In the case of Frasera speciosa, knowledge about its life-cycle can help inform those who use it for economic purposes, e.g., harvesting its roots for medicinal purposes. There is a significant difference in what can be sustainably harvested from a species with a 2 year life-cycle vs. a species with a 20-60 year life-cycle.
Frasera speciosa is known by a suite of common names: monument plant, green gentian, and elkweed (follow links for additional details and photographs).
Posted by Daniel Mosquin at 11:20 AM | Comments (20)
