Today's photographs are courtesy of Ana Margarida Silva of Portugal, who sent them along as a season's greeting to everyone who contributes to Botany Photo of the Day, including readers, commenters, photographers and writers. Claire wrote today's entry:

For a holiday theme, today's post will be about the well-known Euphorbia pulcherrima of the spurge family, Euphorbiaceae. The poinsettia! Called Cuetlaxochitl by the Aztecs, the poinsettia is a native to Mexico and Central America and has been used by humans for centuries before 16th century legend linked the species to Christmas. The Aztecs used Euphorbia pulcherrima as a red dye (from the floral bracts) and also medicinally for reducing fever (antipyretic, much like aspirin). The true inflorescence--a cyathium--is small and grows in the centre of the richly-coloured bracts.

Euphorbia pulcherrima has a long history as a Christmas flower before it was brought to North America in the 19th century by Joel Roberts Poinsett, the Mexican ambassador for the United States. In Mexico, the flowers of the species are sometimes called Flores de Noche Buena (Flowers of the Holy Night -- Christmas Eve). The legend behind this name and its symbolism stems from a story about Pepita, a young Mexican girl, who had nothing to offer as a gift for the birthday of Jesus. Pepita was told by an angel to bring roadside weeds to the church, and as she lay her humble gift on the altar, the weeds miraculously bloomed large red flowers.

The poinsettia is a very popular plant commercially during the holidays (almost all are sold within the six weeks before December 25). A near-monopoly on commercial production existed until the early 1990s in the USA due to a production secret. Euphorbia pulcherrima requires a strict light schedule and temperature regime to produce the vividly coloured bracts, but this wasn't a secret in comparison to how to produce consistent, compact flowering plants. The grafting technique to do this is no longer secret, though, and production has now shifted to parts of the world where labour is less expensive.

If you are worried about poisoning, the tales of toxicity are untrue. Euphorbia pulcherrrima is a mild irritant to the skin and stomach. Copious amounts of leaves ingested would only produce minimal symptoms and discomfort.

Wikipedia has more information on cultivation and images of the many varieties of poinsettia which can come in nearly any color in the wild (except blue or purple) and are cultivated in white, red and pink (though red, unsurprisingly, is the most popular).

Happy holidays!

Of my many enjoyable botanical experiences of 2010, I would rank highly the afternoon I spent with Brian Carson of the Ottawa area in early June. Brian is an avid Trillium enthusiast, and especially keen on finding double-flowered individuals in the wild. Given the rareness of double-flowered trilliums, this necessitates a lot of exploration -- and that experience in seeking out wildflowers in forests made Brian an excellent guide (I don't often get taken to see plants, instead either leading others or exploring on my own). Among other things, Brian took me to see a very densely growing population of hundreds of Cypripedium acaule, or moccasin's flower, growing with little else in the pine needle duff of (what I vaguely recall to be) a Pinus resinosa plantation.

If you're a long-time reader of BPotD and have a sense of plant biodiversity, you'll know that terrestrial orchids of North America are hugely overrepresented on Botany Photo of the Day in proportion to any other grouping of plant species. To me, though, they are some of the first species I recognized as such -- it helped growing up near two ecological reserves in Manitoba set aside specifically for preserving orchid species (Libau Bog and Brokenhead Wetland). However, despite all the orchids nearby, I only remember observing a few plants of Cypripedium acaule in a single location in the Mars Hill Wildlife Management Area during my time there (MHWMA was even nearer to my home). It was a special treat to see hundreds of plants, even though the species itself is widespread in eastern North America and extending into boreal western Canada. In some jurisdictions, it is rare or endangered (e.g., Illinois).

The Manitoba and Quebec locales where I've seen Cypripedium acaule both had the well-draining (sandy) and acidic soils with partial shade typically preferred by the species. I saw two other plants in bloom during that early June trip in Ontario at the Mer Bleue Conservation Area near Ottawa, but these were growing in sphagnum and with more exposure to the sun.

The epithet acaule means "stemless", so named because the flower is borne on a scape: a leafless axis that arises directly from a caudex or rhizome at or near the surface of the ground.

Flora of North America has a scientific description of Cypripedium acaule, while the Digital Flora of Newfoundland and Labrador Vascular Plants has many more images: Cypripedium acaule.

This cultivated specimen of scarlet angel's trumpet or red floripontio was photographed in the Berkeley Botanical Garden this past April. Like all members of the genus, it is native to South America: in this case, the mountain slopes of the Andes from northern Colombia to northern Chile at elevations of 2000-300m (6500-9750ft).

The photograph doesn't provide an idea of scale, so I need to note that the flowers are roughly 20cm (8in) in length. The Preissels, in their book Brugmansia and Datura: Angel's Trumpets and Thorn Apples, note that Brugmansia sanguinea "is the most wonderfully colored of all" members of the genus, with significant variation in number of colours on the flowers (up to three) and range of colours (from brilliant red to pink, orange to light yellow). Intriguingly, flower colour is correlated with temperature, so flowers developing in the summer will be differently shaded than flowers borne in the autumn. Too hot of conditions, however, will lead to flower development being inhibited in this species.

Unlike other members of the genus, Brugmansia sanguinea is not fragrant. Its pollinator (hummingbirds) doesn't rely on scent, but instead homes in on the (typically) red colouration.

Members of the Solanaceae often (always?) contain potent alkaloids. In the case of Brugmansia species, scopolamine and related compounds are found in high concentrations. At extremely low doses (e.g., 330 micrograms / day is cited by Wikipedia), scopolamine can be medicinal for purposes of treating nausea or intestinal pain. Somewhat higher doses were/are taken by indigenous peoples of South America to enter a mind-altering state purportedly used to make contact with the gods or spiritual ancestors. This has led to the occasional modern-day recreational usage, but I would say (in my opinion) only in instances of extreme stupidity given that it is: a) easy to take a fatal dose; and b) painful. Here's an account cited in the book by the Preissels, from J.J. von Tschudi's observations during travels in Peru between 1838-1842 (so in the public domain, I hope):

"The beautiful red Thorn Apple trees (Datura [Brugmansia] sanguinea) grow at the river's edge ... on the less steep slopes of the mountain. The natives call them Huacacachu, yerba de Huaca or Bovachero and use the fruit to prepare a very strong narcotic drink which they call Tonga. Its effect is terrifying. I once had the opportunity of watching how it affected an Indian who wanted to communicate with the spirits of his ancestors. The ghastly scene is so impregnated in my memory that I will never forget it. Soon after drinking the Tonga, the man fell into a dull brooding, he stared vacantly at the ground, his mouth was closed firmly, almost convulsively and his nostrils were flared. Cold sweat covered his forehead. He was deathly pale. The jugular veins on his throat were swollen as large as a finger and he was wheezing as his chest rose and sank slowly. His arms hung down stiffly by his body. Then his eyes misted over and filled with huge tears and his lips twitched convulsively for a brief moment. His carotids were visibly beating, his respiration increased and his extremities twitched and shuddered of their own accord."

"This condition would have lasted about a quarter of an hour, then all these actions increased in intensity. His eyes were now dry but had become bright red and rolled about wildly in their sockets and all his facial muscles were horribly distorted. A thick white foam leaked out between his half open lips. The pulses on his forehead and throat were beating too fast to be counted. His breathing was short, extraordinarily fast and did not seem to lift the chest, which was visibly fibrillating. A mass of sticky sweat covered his whole body which continued to be shaken by the most dreadful convulsions. His limbs were hideously contorted. He alternated between murmuring quietly and incomprehensibly and uttering loud, heart-rending shrieks, howling dully and moaning and groaning. This dreadful condition lasted for a long time until gradually the strength of the symptoms abated and peace was restored. Immediately the women hurried over, and washed him all over with cold water and made him comfortable on some sheepskins. He then slept quietly for several hours. In the evening I saw the man again when, surrounded by a circle of attentive listeners, he was relating his visions and his talks with the spirits of his ancestors. He seemed to be very tired. His eyes were glassy, his body was limp and his movements were lethargic."

And, in case that isn't enough to dissuade, here is a search on Google for fatal Datura with results pointing to a number of separate incidences of death (often young and male). Datura is a close relative of Brugmansia, with the same set of alkaloids.

Anemone richardsonii is the only yellow-flowered species found in northern climates. The occurrence map from the USDA PLANTS database is somewhat deceptive, as it shows Alaska and most of Canada. While accurate, it isn't as precise as the distribution map for Anemone richardsonii from the Flora of North America, which demonstrates far more clearly that this is a species of northern climates. In addition to northern North America, yellow thimbleweed or yellow anemone is also native to Greenland and parts of Eurasia.

Found in somewhat open areas (FNA notes: thickets, moist woods, meadows, slopes; 20-2200 m), the plant in today's photograph was growing in a wet seep area at lower elevations of Pink Mountain in northeastern British Columbia. The population of 75 or so plants was the only one we noticed during the 4-5 days I was there. Another botanical description of the species is available from the Flora of the Canadian Arctic Archipelago and many more images from E-Flora British Columbia.

Its specific epithet, richardsonii, is in honour of Scotland-born surgeon-naturalist Sir John Richardson--a fascinating and accomplished person. In addition to seemingly having every fifth species of plant in northern Canada named after him (well, that's a bit of an exaggeration, but there are many), as an icthyologist he described 43 genera and over 200 species of fish. He was the surgeon-naturalist on the first two of Franklin's expeditions to the northern reaches of North America; when Franklin's third (ill-fated) expedition did not return, he traveled by canoe from Sault Ste. Marie, Ontario to the mouth of Mackenzie River--a distance of 3800 km / 2350 miles as the crow flies--in 3 months. In 1848. At age 60. Yet more impressive, in order to see the Arctic spring bird migration in 1827 on the Saskatchewan River, he walked from Great Slave Lake to Fort Carlton (where he was to meet his assistant, Drummond). This was a distance of over 1450km / 900 miles. He made the journey in 50 days. From December 25 to February 12. Read more: C. Stuart Houston's account of Sir John Richardson in Arctic Profiles (PDF).

Nemophila menziesii has previously been featured on BPotD, but with very little write-up, so I'll rectify that today.

Nemophila means "woodland-loving". Of the few times I've observed baby blue-eyes, most have been on the margins of forested areas. Nemophila is strictly a North American genus, with a couple species occurring in the southeast USA and the other nine in western North America. Nemophila menziesii is common in California, Oregon and Baja California. The USDA PLANTS database reports it as also occurring in Wyoming (via a personal communication) and an introduced species in Alaska (!).

Even though baby blue-eyes is always cheering for me to see, I don't share the same thoughts about its family (the Hydrophyllaceae) in general, having been irritated by the hairs on the plants of some of its familial relatives like Phacelia. That said, I do admire the family for its tenacity, with some representatives able to grow at the "green edge" of very dusty gravel roads, others able to handle well-draining sandy soils of deserts and yet others managing to be among the first to bloom in the cold mud of still-melting snowbank margins. Nemophila menziesii, however, prefers more moderate habitats; the Jepson Manual treatment for Nemophila menziesii mentions "meadows, fields, woodlands, roadsides, grasslands, canyons".

CalPhotos has an extensive image collection of Nemophila menziesii, including many flower colour or pattern variants.

Claire wrote today's entry:

Thank you to Tony Foster (Tonyfoster@Flickr) of Kaeo, New Zealand, for this close-up of the inflorescence of Knightia excelsa. The photograph was made during full bloom in October of last year, and submitted via the Botany Photo of the Day Flickr Pool. Check out Tony's Phytography weblog!

Knightia excelsa, otherwise known as rewarewa, is a Proteaceae native to New Zealand in the North Island and Marlborough Sounds of the South Island. It is one of only three species of Knightia (the other two are native to New Caledonia). Also known as "New Zealand honeysuckle", rewarewa is the more widely used name, and of Mäori origin. Knightia excelsa has a cultural importance to the Mäori people; it has been suggested that the large seed-pods (a link to Tony's weblog) of this evergreen tree are the exact model of Mäori canoes (PDF) (they make excellent toy canoes, as well).

Knightia excelsa has other practical applications in honey production and woodworking. The attractive timber is light, grainy, and reddish-orange; it is most commonly used for ornamental inlays and smaller items as it is not durable and retains a lot of moisture (I suggest an image search for rewarewa wood to get an idea of what woodwork with this species looks like).

Since the image today is of the flowers of Knightia excelsa, it is also worth noting that they are pleasantly fragrant, rich in nectar, and mostly bird-pollinated. The fascinating inflorescence is likely meant for decreasing cross-pollination and making the nectar reward accessible to frequenters like tuis and bellbirds.

Claire is responsible for writing today's entry:

Robert Klips (Orthotrichum@Flickr) provided us with this photograph of the flowers of Apios americana via the BPotD Flickr Pool, taken August 22, 2009 in Pickaway County, Ohio, USA. Thank you, Robert!

Apios americana is a legume (Fabaceae) native to eastern & central USA and eastern Canada. I thought this particular species worth writing about as it is very well known for its starchy, edible, tuberous rhizomes. Commonly called "groundnut" or "hopniss", Apios americana was a crucial food source for North American indigenous peoples and early British settlers. The edible parts of the plants include the swollen nodes of the underground rhizomes. The tuber is high in starch and even moreso in protein (3x that of potato!). The species was considered a potential saviour to the Irish potato famine. Unfortunately, domesticating Apios americana, something the English tried in both 1635 and 1845, proved to be unfavorable as the tubers take two to three years to mature and did not take well to conditions in Britain (the vegetative structures do not thrive in frost). It has also been noted that the native peoples of the eastern United States were unable, or unwilling, to fully domesticate the species. Sometimes, seed was spread around villages in hopes to increase its frequency in populated areas, as the tubers were extensively collected.

The taste of Apios americana is comparable to that of a sweet potato--the tuber can be baked, boiled, dried and probably whatever other method of cooking you can think of. If you happen to be collecting in eastern North America, the vegetative parts of groundnut look very much like the cultivated pea vine one would find in a garden, but grows wild in the woods. Along with the tuber, the seeds and seedpods are also cited to be edible, though they are not produced in great quantity. Of course, also look for the lovely hooded flowers. The blossoms utilize a "tripping" mechanism; for those who don't know, when the keel, or bottom petal, is landed on by a bee, an explosion of pollen covers the insect and the pistil is then exposed and ready for a new pollen bearer. This is a pollination mechanism common in the Fabaceae.

It's likely I've expressed in the past my love/hate relationship with this genus. Love to be in their presence, love to photograph Castilleja, but hate to identify them. I'm hoping I have the identification correct in this case. I wrongly assumed all of the paintbrushes that looked like this at the high elevations of Steens were the same taxon, but the key in Flora of Steens Mountain suggests otherwise.

Wavy-leaved paintbrush is found in western North America. The variety pinetorum is native to Idaho, Oregon, Nevada and California, where it grows in dry places. Depending on the reference, at least a few other varieties are sometimes recognized in the Great Basin area. On Steens Mountain, Castilleja applegatei var. pinetorum is commonly found growing in association with sagebrush at higher elevations (above 2000m (6561 ft)). Having visited Steens Mtn three times in the past 4 years, 2007 seemed to have been a banner year for the local population with thousands of individual plants dotting the landscape. This photograph is from 2009, though, when plants were more often found in small pockets of the landscape.

Moerman's Native American Ethnobotany Database lists this taxon as being used as a beverage by the Miwok peoples, who occasionally sipped the flower for its nectar, something I suppose I will have to try on my next occasion to visit the area.

Like other members of its genus, Castilleja applegatei var. pinetorum is a hemiparasite (via haustoria). Though it does not to parasitize to survive (the species is chlorophyllous, after all), parasitizing other species can produce more robust, longer-living plants. In the case of Steens Mountain, I suspect the host plant is typically Artemisia tridentata, or big sagebrush.

Let's conclude the medicinal plant diversity series with a species originating in Mesoamerica. Today's photographs are courtesy of Forest & Kim Starr, the photographers behind many of the images on the Hawaiian Ecosystems at Risk project. These images, plus many more, can be found on the photographs page for Dysphania ambrosioides (here labeled under a synonym, Chenopodium ambrosioides).

As implied above, Dysphania ambrosioides has readily spread (in some places, invasive) from its native southern North America to northern South America range to tropical and warm-temperate regions around the world (modern distribution in northern North America). Common names abound for the species, ranging from American wormseed to paico (Peru) and epazote (Latin America) to erva de Santa Maria (Brazil).

Dysphania ambrosioides has the quality of being both a spice and a traditional medicinal herb. Gernot Katzer's excellent Spice Pages has the details on epazote as a leafy herb, including its common names in 32 languages and its use in Mexican cuisine for foods such as refried beans (added due to its antiflatulent properties).

On the medicinal side--and in addition to its use as an antiflatulent--wormseed or wormwort was long-used globally as an antihelminthic, a drug that helps expel intestinal worms. The most medicinally active compound in Dysphania ambrosioides is ascaridole, present in its oil. In particular, there is a cultivated type of Dysphania ambrosioides known as Chenopodium ambrosioides var.? subsp.? anthelminticum (or sometimes Chenopodium anthelminticum) that is grown for its high concentrations of the chemical in the seed oil (the taxonomy is very uncertain here, not sure if the cultivated type is botanical or horticultural in origin). Use of Dysphania ambrosioides as an antihelminthic, however, declined significantly in the 1930s as less toxic medicines for treatment were developed, retreating from mainstream use in Europe, North America and South America to only being used significantly as a traditional medicine in its native Mesoamerica.

Cornell University's Medicinal Plants for Livestock: Dysphania ambrosioides gives an excellent account of the history of the species in cultivation and discusses the extreme toxicity of the oil (2 teaspoons of the oil can kill or adversely effect an adult sheep). It also warns "The dose that causes adverse effects is very close to the dose that is supposed to be efficacious. Therefore, extreme caution should be used when treating an animal with this plant or the oil made from the plant.". It should also be noted that in high concentrations, it is used as an insecticide.

Few references mention this, but the species has also received a recent examination as a candidate drug for cancer treatment: see Efferth, T. et al. 2002. Activity of ascaridol from the anthelmintic herb Chenopodium anthelminticum L. against sensitive and multidrug-resistant tumor cells. Anticancer Res. 22(6C):4221-4.

Today's entry continues the medicinal plants diversity series, though I've not been able to find a reference to medicinal use of this particular species. However, other species in the genus are used in treatments (due to the same compounds in the roots), so it isn't a stretch to imagine it has medicinal potential.

I became aware of the medicinal uses of Coptis while researching economic values of members of the buttercup family for my presentation to the Native Plant Society of BC last week. Modern economic uses for this family, beyond ornamentals, are few and far between, but the genus Coptis stands out. As one example, an eastern Himalayan relative of today's species, Coptis teeta, is a prized Ayurvedic herb. Known as Mishmi (from the Mishmi Hills of Arunachal Pradesh), its roots contain berberine and it is used to treat gastrointestinal complaints and malarial infections. Due to a combination of deforestation and overharvesting, however, Coptis teeta has been brought close to extinction. Other members of the genus have also been used medicinally by their respective local indigenous peoples, including Coptis chinensis (China), Coptis japonica (southeast Asia) and Coptis trifolia (North America) (ref: The Cultural History of Plants, ed. Prance and Nesbitt, but also see: WHO Monographs on Selected Medicinal Plants - Volume 1, pp. 105-144).

Discussion on the pros and cons of berberine as a medicinal compound are difficult to find in specific relation to Coptis, but another member of the Ranunculaceae makes a good substitute. The increasingly-threatened goldenseal (Hydrastis canadensis) has been somewhat well-studied as an antibacterial and anti-inflammatory due to its high concentrations of berberine; you can read about some of the evidence (or lack thereof) via the University of Maryland Medical Center: Hydrastis canadensis, or the Dietary Supplement Database from the University of California, San Diego: Hydrastis canadensis. As an aside, the reasons for the decline of Hydrastis canadensis in its native range of eastern North America are unsustainable harvesting and mountaintop removal mining.

Coptis laciniata is commonly known as Oregon goldthread, and this low-growing perennial is found in wet coniferous forests on the west side of coastal mountain ranges from Washington to California. For additional photographs, see the Burke Museum's entry for Coptis laciniata or CalPhoto's Coptis laciniata image collection.

Claire continues with the medicinal plant diversity series:

Thank you to Marianne (marcella2@Flickr) of Alkmaar, Netherlands for this gorgeous photograph of Hypericum perforatum, or St. John's wort, provided via the BPotD Flickr Pool. Zeer gewaardeerd!

Hypericum perforatum is known as common St. John's wort -- the name "St. John" stems from the traditional harvest time of Hypericum perforatum during the day of St. John on June 24th. The species belongs to a genus that includes a whopping 370 species worldwide. It has spread, via introduction, to temperate and subtropical regions in North America and Asia, with origins in Europe. Sadly, it is an invasive species or noxious weed in many countries, particularly because it is very toxic to livestock and can be lethal.

Contrasting to the effects it can have on animals, Hypericum perforatum's primary medicinal application is treatment for mild to intermediate forms of depression. It has also been used for less serious maladies like scrapes and cuts (early studies show some positive results for having antibacterial properties against gram-negative bacteria). The most medicinally-active chemicals in Hypericum perforatum are hypericin and hyperforin, which have proven to be effective in treating depression . These chemicals may function as inhibitors of monoamine oxidase, a compound associated with the illness. A study published in the Cochrane Database of Systematic Reviews suggests common St. John's wort is more effective than a placebo and equivalent to tricyclin antidepressants for short-term treatment. St. John's wort contains many other compounds (including oils, tannins, and flavinoids) that have been suggested as medicinal, though further research is needed.

Hypericum perforatum can be a lovely ornamental in gardens, drank as an herbal tea (though the taste, I was told, is a bit peculiar) and produces colours for dyes: a pleasant purple when the buds and fruits are crushed and yellow when the flowers are used. Needless to say, this is an intriguing and important species that could take some more looking into!

Claire continues the medicinal plants series, and writes:

Thank you to Meighan (Meighan@Flickr) of Vancouver, Canada for these photograph of a fascinating shrub, Leonotis leonurus (via the BPotD Flickr Pool). Original images are here and here. Thank you, Meighan!

To some, Leonotis leonurus is best known as wild dagga (a name sometimes used for Cannabis sativa, but note that Leonotis leonurus has no biological or chemical relationship to Cannabis sativa). However, to gardeners, one of its "lion" common names (lion's ear, lion's claw, lion's tail) is more often applied to this lovely perennial shrub with bright orange pubescent flowers.

The species is relatively hardy as well as being tolerant of drought. In South Africa, it is found in grasslands where it grows among rocks. Of the nine recognized species of Leonotis, Leonotis nepetifolia is the only one naturally found outside of Africa (in southern India).

Leonotis leonurus is classified in the mint family, Lamiaceae (formerly Labiatae). The Lamiaceae is chock-full of aromatic, herbal, and medicinal plants such as oregano, lavender, sage, rosemary, marjoram, thyme and teak, to name just a few. The medicinal properties of Leonotus leonurus are well-known to African and east Asian cultures (the species has naturalized through much of the tropical world). The Zulu and Xhosa peoples of southern Africa (along with others) utilize this plant for both human and animal medicine, including treatment of respiratory symptoms, snake bites, and skin ailments. Premarrubiin and marrubiin are two compounds present in the plants that may be linked to healing effects, as similar compounds are used in the treatment of wet coughs and bronchial disease. Leonurine, an alkaloid present in the leaves, shoots and flowers, is a well-known active compound in some communities -- it is documented to have mild sedative and euphoric effects when smoked, hence the name "wild dagga". Indeed, Leonotis leonurus was used by the Khoikhoi people as an inebriant (PDF).

I would think the majority of us prefer to enjoy lion's ear in our gardens, as the flowers attract bees and butterflies in addition to their beautiful orange colouration. Since it has a late flowering season, I'm hoping that Meighan's lion's ear survived the cold front we had last week, so that it can be enjoyed just a little longer.

Well, I had hoped to have this posted early today (Thursday still, for me), but events such as network outages and poor weather conspired against me. I suppose American readers will just have to enjoy the cranberry photograph with their Thanksgiving leftovers. This image was made a few weeks ago at a cranberry field near to where I live. Every morning when home, I look out on the field, and this year finally made the time to go photograph when I saw that the field had been flooded, the fruit was floating, and harvesting was underway.

Claire writes the rest of today's entry, which begins a series on "Plants and Medicine" as part of UBC Botanical Garden's themes for the International Year of Biodiversity. Claire writes:

For my American Thanksgiving, I always remember my parents buying gelatinous cranberry jelly, and chunky cranberry jam. Much to my dismay, I was the one that had to open cans of the stuff and scoop it into bowls for the feast. It was certainly not my favourite, and I always wondered why people were so enamoured with the sticky, red and very tart substance. As it turns out, cranberries transcend more than just an old-time Thanksgiving tradition.

The photograph shows an unknown cultivated variety of Vaccinium macrocarpon (large cranberry or American cranberry), which is native to eastern Canada, eastern United States and the Territorial Collectivity of Saint Pierre and Miquelon, with a range reaching as far south as the mountains of Tennessee and North Carolina. In the heath or heather family, Four species of Vaccinium are recognized as cranberries. These are: Vaccinium macrocarpon, Vaccinium oxycoccus (common cranberry), Vaccinium microcarpum (small cranberry), and Vaccinium erythrocarpum (southern mountain cranberry). British Columbia is one of the major Canadian producers of cranberries, along with eastern Canadian provinces such as Ontario, Nova Scotia, and Quebec. In the United States, Wisconsin is the largest producer. Massachusetts and Minnesota are a few of the other major US producers. Vaccinium macrocarpon (PDF) grows on low woody vines and is cultivated in sand beds until the autumn when the fruit is ripe and red. The beds are then flooded and the berries float on the water surface where they are collected to be made into jams, sauces, juices, dried snacks and more.

The enthusiasm for Vaccinium macrocarpon and related species dates back centuries. Native peoples of North America used cranberries as food, dye and medicine long before European arrival and subsequent cultivation.

Perhaps you have heard that cranberry juice may help with urinary tract infections, ulcers, kidney stones, and a variety of other ailments. Some studies have shown that the juice of Vaccinium macrocarpon has anti-bacterial effects. One of the studied mechanisms is preventing bacteria with fimbriae (small hair-like projections) from being able to attach to cell membranes (and therefore hinder infection). A study by Yamanaka et al. published in Oral Microbiology Immunology in 2004 yielded similar results regarding the inhibition of bacterial adhesion, this time with respect to the usefulness of the juice preventing dental plaque build-up. Interesting stuff!

The Mayo Clinic has a list of medical conditions for which cranberries are purported to some sort of medicinal value, ranging from antioxidant properties to memory maintenance. However, in all instances, more evidence through additional study and research is needed to verify or disprove the touted properties. Evidence to date, though, is strongest for cranberries being useful in the reduction of the ability Helicobacter pylori bacteria to live in the stomach and cause ulcers and in the prevention of urinary tract infections. So, next time you have Vaccinium macrocarpon sauce for Thanksgiving, you may want to take an extra spoonful!

Claire again wrote today's entry:

Thank you to sweller of the UBC Botanical Garden Forums for this photograph of Pachycereus weberi (via the BPotD Submissions Forum).

Pachycereus weberi is known as candelabro, or Cardón Espinoso (the common name being an obvious reference to the resemblance of plants to candelabras). Its distribution ranges across desert scrub and deciduous forests of the southwestern Mexican states of Guererro, Puebla and Oaxaca. The genus has a native range of southern Arizona to Central America, and also includes the tallest cactus species, Pachycereus pringlei (an individual grew to 19.2m/63ft). In Pachycereus weberi, plants "only" reach approximately 10m tall and as nearly as wide.

Pachycereus weberi only produces white or yellow flowers. These bloom at night, with bats being the pollinators (as is common in the genus). The edible fruit has spines which dehisce when the fruit matures, possibly a mechanism to prevent eating of the unripe fruit. These spines (modified leaves), extend from the thick stem in a beautiful pattern (see some close-ups via Google Image Search). The seeds of the ripe fruit of Pachycereus weberi can be harvested and ground into a flour.

Thanks once again to Claire for writing today's entry:

This photograph of Hibiscus laevis was taken in July, 2007 by Robert Klips (Orthotrichum@Flickr) of Franklin County, Ohio, USA via the BPotD Flickr Pool. Thank you Robert!

Hibiscus laevis of the mallow family, Malvaceae, is a native to eastern and central North America. The five delicate petals are arranged in a whorl pattern and are imbricate (overlapping), with the flowers reaching up to 13cm (5 inches) across. It's interesting to note that Hibiscus laevis only has one mature flower in bloom each day during its bloom season.

Halberd-leaved rose mallow or scarlet rose mallow are the common names for this species (a halberd is a medieval weapon, while the scarlet appellation is due to the deep red throat occurring in most flowers). The green lantern-like features on the plant in the photograph are flowers in bud, enfolded by huge sepals.

Hibiscus flowers have a bit of an unusual structure. Hibiscus laevis has a central column that bears both the male and female reproductive organs. Five female pistils are present at the top of the column, and the column is then surrounded by numerous anthers emerging from fused filaments (a monadelphous stamen arrangement). This prevents self pollination and promotes bee pollination quite effectively as the anthers (pollen-bearing) and the stigma (female organ) are separated by space. For additional images, including photographs of leaf shape variation and a closer look at flower parts, see AlabamaPlants: Hibiscus laevis.