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Botany Photo of the Day
In science, beauty. In beauty, science. Daily.

Jan 30, 2015: Nelumbo nucifera

Tamara Bonnemaison is the author of today's entry. She writes:

Thank you to apasar@Flickr for these two lovely photos of Nelumbo nucifera or sacred lotus (do browse apasar's photostream for additional photographs!). The sacred lotus has been featured briefly once before on Botany Photo of the Day in this entry: Nelumbo nucifera.

The sacred lotus is one of only two species in the Nelumbonaceae, and can be found growing wild from southern Russia to northern Australia. The other species in this small family is Nelumbo lutea, which grows in eastern and southern North America. Up until fairly recently, the Nelumbonaceae was placed in the Nymphaeaceae, or water lily family. Recent molecular studies have shown that the sacred lotus is not closely related to water lilies, and that its closest living relatives are instead the plane trees (Platanus spp.). It is now believed that the similarity of lotuses to water lilies can be explained through convergent evolution, meaning that they independently evolved similar traits because they occupied similar environments. Nelumbonaceae now constitutes its own family, and can be easily identified by its leaves and flowers that are raised above the water on stalks, as opposed to the leaves and flowers of water lilies, which float on or below the water's surface.

The sacred lotus has a long history of use, and is sacred to Hindus and Buddhists, symbolizing beauty, purity, fertility and divinity. There is an abundance of literature, folklore, and imagery available about the sacred lotus, which makes it both easy and difficult to write a short entry about. What to cover, what to leave out?

A short botanical description seems in order. Nelumbo nucifera is an aquatic perennial with beautiful, showy flowers. Its rhizomatous roots anchor to mud in shallow water bodies, and its leaves are held above the water on long stalks that join the round leaves at the centre of the blade (this leaf attachment is termed peltate). The flowers come in white, pink or slightly yellow, and are held above the leaves for a period of two days, closing overnight. At the base of each flower resides an unusual spongy receptacle that is obconical and truncate in shape. Apasar's close-up shows the yellow receptacle beautifully; the strange "googly eyes" are the many separated ovaries bearing sessile stigmas embedded just below the truncated top of the receptacle. One final note - sacred lotuses are extremely long-lived, with individuals living upwards of a thousand years. Seeds can remain viable for an even longer time period.

Of the many cultural, spiritual, scientific and horticultural aspects of this species that I could highlight, the one that strikes me as particularly fascinating today is the "lotus effect". The sacred lotus grows in mucky, swampy environments, yet its leaves emerge from the water perfectly clean. This characteristic drove Buddhists to revere the sacred lotus as a symbol of purity, and now drives engineers to study it in order to develop substances that mimic its self-cleaning mechanisms. The development of high-resolution electron microscopes in the 1960s allowed researchers to study the nanostructure of leaf surfaces, and since that time a clear picture of how plant surfaces self-clean has emerged. The sacred lotus, and other self-cleaning species, have surfaces that are superhydrophobic, or extremely water-repellant. Although a lotus leaf appears waxy and smooth to the naked eye, it is actually covered by microscopic bumps that minimize the point of contact between the leaf's surface and the water droplet, allowing the water droplet to roll off the leaf's surface even at very low angles, picking up dirt and other particles along the way. All of this is achieved through the structural surface of the leaf, and is explained very well in the article, "The Dream of Staying Clean: Lotus and Biomimetic Surfaces" (PDF).

These same principles are now being applied to engineered surfaces to create paints, clothing, building materials and other objects that are water repellant and self-cleaning. Lotus-like nanosurfaces can now be found on the inside of ketchup bottles (to get out the last drop of ketchup) and on the outside of buildings (to keep the building clean and free of mold). Use of the lotus effect is a great example of biomimicry, which is "an approach to innovation that seeks sustainable solutions to human challenges by emulating nature's time-tested patterns and strategies. The goal is to create products, processes, and policies--new ways of living--that are well-adapted to life on Earth over the long haul". See biomimcry.org for more.

Jan 29, 2015: Iris unguicularis

Iris unguicularis

We've had a mild winter in the Vancouver area so far, with only one week of daytime freezing temperatures early in the winter. It is now one of those years where we are seeing noticeable early bloom times on some of the plants in the Garden. As of the final week of January, there are at least a couple dozen taxa in bloom. If the weather persists, it may be one of those years where the first magnolias blossom in early March, if not late February.

This Algerian iris was photographed yesterday afternoon in the E.H. Lohbrunner Alpine Garden here at UBC. Nearby, I also photographed what was going to be the original subject of today's posting, something labeled Crocus rujanensis. However, after reading some discussions about how to identify that species, it looks like we will have to verify the identity of that accession. There is no doubt about the identity of this iris, however, as it is one of the few irises that flower during winter (another common name is winter-flowering iris). Its native range includes Algeria, of course, but also adjacent Morocco. It can also be found in Greece (including Crete), Syria, Lebanon, Turkey and Israel. In the Jerusalem Botanical Gardens, it flowers from autumn through spring. Here in Vancouver, it may perhaps flower as early as December (though I didn't notice it), as we would have a similar climate and corresponding bloom time to parts of southern England (read Vita Sackville-West's 1950 account of this plant here: "From the archive: the iris that thrives on sun and poverty").

The suggestion of thriving on poverty is in reference to the ability of this species to prosper in poor soils. As well, it is known to be drought-tolerant. To top off these qualities that make it a choice species for what can be a difficult gardening situation, it is also sweetly and lightly fragrant. I noticed this when photographing it. Some writers suggest to use it as a indoors cut-flower, as it is long-lasting and this is a particularly good way to enjoy the scent.

Jan 27, 2015: Eucalyptus tetraptera

Eucalyptus tetraptera

Another entry from Tamara Bonnemaison today, who writes:

Thank you to Mike Bush (aka aviac@Flickr) for submitting this intriguing photo of one of the strangest flowers that I have ever seen. Mike managed to capture two Eucalyptus tetraptera flowers at different stages of development, with a flower having stamens curled up in a "doughnut" shape on the left and then elegantly unfurled on the right.

Living in Vancouver, I rarely come into contact with Eucalyptus, as so few of these species are hardy enough to withstand the occasional extreme cold the area receives. So it was with surprise that I came across this photo of the lush flowers of square-fruited mallee and learned that they come from a species of Eucalyptus. Eucalyptus is a large and diverse genus, and an article in Pacific Horticulture makes a strong case for greater inclusion of the mallees, or small and multi-stemmed species of eucalyptus, in western American horticulture (the article claims that Eucalyptus had fallen out of favour in the region due to invasiveness of some of the tree species). Of the many potential candidates, Eucalyptus tetraptera does not have the stateliest growth form - today's photographer Mike Bush describes it as "a messy straggle of branches in a messy pile" - but its bright and unusual buds, flowers and fruit make this species well worth planting wherever it will grow (sadly, not likely to survive this far north).

Square-fruited mallee has a limited distribution in Western Australia, growing only on coastal sandplains at the southern margin of the continent. Its scraggly branches reach a height of about 2.5 meters, and it has very thick, leathery elliptical to lanceolate leaves. Like most eucalyptus, square-fruited mallee has an operculum or bud cap that falls off to reveal a flower composed largely of stamens. You may notice from Mike's photo that the flower lacks petals: the petals in nearly all eucalyptus (with the exception of Angophora species) join at an early stage of bud development to form the inner operculum and the sepals join to form the outer operculum. Today's photo shows a flower which has just lost its operculum. The square hypanthium forms the base of the flower. This hypanthium will mature into a 5cm wide fruit that will remain bright red or pink for most of the year. The woody fruits of Eucalyptus are commonly called gumnuts.

If you are interested in learning more about Eucalyptus, the Euclid website is a fabulous resource. For those of you looking for a lighter take on Australian plants, here is an article on the children's author May Gibbs, who created characters of common Australian seeds & fruits, including the banksia man and the famous gumnut babies.

Jan 21, 2015: Canarina eminii

My apologies for the week+ gap in entries. I'm recuperating from one of the worst colds I ever remember having. To the more important things, here's an entry written by Tamara Bonnemaison:

Today we have two beautiful shots of a Canarina eminii flower (second image), freshly submitted to the Botany Photo of the Day Flickr Pool by Christopher Young (aka c.young@Flickr). Thank you Christopher!

Canarina eminii is a herbaceous perennial native to eastern tropical Africa, from eastern Democratic Republic of Congo to Ethiopia and south to Malawi. It can grow either as an epiphyte or on rocky ground, and occurs in upland and riverine forests. It is one of three species in the genus, the others being Canarina abyssinica and Canarina canariensis (all are native to Africa and the Canary Islands). Canarina eminii needs high light intensity, and its ability to grow as a twig epiphyte allows it to establish high in the tree canopy. The other species of Canarina must contend with being rooted in the ground, and climb over other plants to maximize their access to sunshine.

This species possesses an ornithophilous flower, meaning that it is pollinated by birds. The blue-headed sunbird, Cyanomitra alinae is one of the numerous avian species that enjoys the nectar supplied by this flower, pollinating it in exchange. Today's photos show two features that are typical to ornithophilous flowers: bright colouring (although red is most common), and a long tube-shaped corolla. Another feature that you cannot see from the photographs is that this flower's nectar has a high ratio of hexose sugar, as opposed to most insect-pollinated flowers that are high in sucrose. Interestingly, Canarina eminii is one of a few species listed by Gerald Mayr in Paleogene Fossil Birds as appearing to be adapted to hummingbird pollination, but occurring in the Old World where no hummingbirds can be found. Canarina eminii lacks a perch, requiring its pollinators to hover. Mayr suggests the possibility that the species co-evolved with a hummingbird species that has since become extinct in Africa. I wonder, though, if instead it is adapted to Africa's version of the hummingbird, the sunbird. According to a podcast about the blue-headed sunbird published by Uganda's National Forest Authority, some sunbirds are able to take nectar by hovering, but must perch to feed.

If any of you resided in Uganda or corresponded with someone who did around ten years ago, you may have received an image of Canarina eminii in the mail, as this species was chosen as one of eight "flowers of Uganda" featured on a set of stamps.

Jan 9, 2015: Pararchidendron pruinosum

Pararchidendron pruinosum

...and another entry today by Tamara Bonnemaison, who writes:

Thank you Andreas Lambrianides (aka andreas lambrianides@Flickr) for submitting this photo of the fruits of Pararchidendron pruinosum. Andreas frequently contributes to the Botany Photo of the Day Flickr Pool, favouring striking botanical images set against a black backdrop. Thank you Andreas!

Pararchidendron pruinosum is a small tree native to the rainforests of Australia, Indonesia and Papua-New Guinea. In Australia, the species ranges from north Queensland to New South Wales. It is loved by many Australian native plant enthusiasts, and has quite a few common names that illustrate its different characteristics. The name "monkey's earrings", for example, is a colourful describer of the twisted yellow fruit pods that open to show their red lining and shiny black seeds. I can imagine a troop of monkeys draped in these pods like children swathed in costume jewellery.

Another of its common names, snow wood, describes the appearance of the tree when it bears fluffy white flowers opening in autumn. The flowers then yellow with age, and are borne on inflorescences growing in dense clusters on 3.5-10cm long peduncles (stems supporting the inflorescence). Another of Andreas Lambrianides' photos shows the progression of the flowers very clearly--first as green buds yet to open, then to white and finally yellow as the flower matures (see another photo of these by Tony Rodd). These "pompoms" can be up to 20mm. in diameter, are slightly fragrant, and are impossible to ignore in a garden setting. Like people, butterflies love the flowers, and (in Australia, at least) snow wood is a host plant for tailed emperors (Polyura pyrrhus), a species of butterfly native to Queensland.

A third common name given to Pararchidendron pruinosum is less complimentary. The name "stinkwood" refers to the scent of this species when it is being cut down. I was not able to find a source that described which compounds are responsible for the smell, but did learn that the bark is a beautiful reddish-brown and that the trunk grows as a perfect cylinder without any buttressing. The wood does have some ornamental qualities, but overall it seems like this species is a great one to plant, but not to remove.

Jan 8, 2015: Parmelia sulcata

Parmelia sulcata

Today's entry was written by BPotD Work-Learn student Cora den Hartigh. Cora writes:

Robert Klips (aka Orthotrichum@Flickr) contributed today's photograph. This species of lichen was growing on a rural cemetery headstone in Marion County, Ohio. Thank you!

This lichen never fails to remind me of summer, though it is a snowy-looking subject. Parmelia sulcata, or hammered shield lichen, is a silvery foliose species in the Parmeliaceae with a dark, nearly black, underside possessing dense rhizines (hair-like growths from the body that anchor the lichen to the substrate). The photobiont of this symbiont is a green algae in the genus Trebouxia (one of the most common photosynthetic partners in lichen relationships). Parmelia sulcata is a very common lichen throughout Europe and North America, but it was particularly brought to my attention last summer when I discovered a hummingbird nest with this lichen species laced in. For an example of what I observed, visit the web site of Karen Crowe and browse her wildlife images gallery.

Hummingbirds are the only family of birds to have mastered flying backwards. North American species such as rufous or ruby-throated hummingbirds collect Parmelia sulcata in their beaks and drop it cleverly and carefully into a sticky web of spider silk. Once enough lichens are collected, the silk strands are laced about to form a cup, which is filled with fluffy seed down and moss to form a tiny nest maybe about the size of a toonie (~30mm or 1.25" in diameter). The lichens do double duty as highly effective camouflage amongst conifer needles or hardwood foliage! Using lichens in this way is not uncommon and some birds will actually "shingle" their entire nests! Although a few different lichen species are used, Parmelia seems to be the favourite by far, although this could be because it is highly tolerant of pollution and therefore very common. You can find a full list of lichens' faunal users at the Lichens of North America Wildlife page.

In the presence of K+ (potassium hydroxide, or caustic soda, available at hardware stores), the cortex or outermost layer of this lichen will flash orange-yellow (for examples, an orange result and a yellow result)! This is a chemical reaction that indicates the presence of a secondary metabolite called salazinic acid, which has demonstrated antibacterial and antifungal activity.

If you are interested in chemical identification of lichens, the British Lichen Society has an excellent resource page on chemical tests. More examples of spot tests are available from Sharnoff Photos: Lichen Spot Tests.

Jan 7, 2015: Lindernia monroi

Botany Photo of the Day returns with some small updates to the underlying software and an entry written by Botany Photo of the Day Work-Learn student, Tamara Bonnemaison. Tamara writes:

The colours in the photographs (image 1 | image 2) that Bart Wursten (aka zimbart@Flickr) took on his vacation to the Matobo Hills of Zimbabwe are breathtaking. The subject: the delicate Lindernia monroi. Thank you Bart for posting these two photos to the Botany Photo of the Day Flickr Pool.

Commonly known as Dongola snapdragon, Lindernia monroi is a rare but widespread annual herb found only in Zimbabwe. It grows to about 13cm in height, and has somewhat fleshy, crowded basal leaves. The pale pink to white snapdragon-like flowers are borne on long, slender pedicels. Lindernia monroi has a yellow palate, which is a projection on a tubular flower's throat. In some instances, the palate closes off the corolla to unsuitable pollinators, while in other instances, the palate acts as a landing pad to desirable pollinators (and presumably could function as both). I was not able to find any information about specific pollinator relationships that this species may have.

Lindernia monroi is a poikilohydrous aquatic species, meaning that it has the ability to tolerate dehydration and recover with little physiological damage. It is found in small granitic depressions that are seasonally filled with water, growing alongside other species that have the ability to revive from desiccation. These types of species are sometimes referred to as resurrection plants, and the majority of Lindernia species may be described in this way. The Matobo Hills, where these two photos were taken, have an unusually varied and interesting granitic terrain, and Dongola snapdragon often grows on the inselbergs, or large individual vertical rocks, which are found in the area. The inselbergs act as islands in the landscape, creating many microclimates and generating high species diversity. This rich ecosystem, with a long history of cultural importance and use, has been designated as the Matobo Hills UNESCO World Heritage Area.

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