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Preview: Botany Photo of the Day

Botany Photo of the Day

In science, beauty. In beauty, science. Daily.

Updated: 2016-02-16T22:00:40Z

Copyright: Copyright (c) 2015, The University of British Columbia Botanical Garden and Centre for Plant Research. NB: See individual entries for license to use information.

Stellarioides tenuifolia


Tamara again: another thank you to Bruce Brethauer (aka Glochidman@Flickr) for these beautifully-photographed images of Stellarioides tenuifolia buds and a flower. Researching this species was difficult, since I was not sure which name to use. Until fairly recently, the flowering herb shown today was known as Ornithogalum tenuifolium. This is the label given on an early 19th century botanical illustration by Pierre-Joseph Redouté, and the name seems to have been valid until the current century. In 2009, John Manning and his colleagues used DNA sequence data to reclassify this species as Albuca virens. This name was quickly contested in 2011 by Martinez-Azorin et al., who found two clades within subfamily Ornithogaloideae (Hyacinthaceae), rather than Manning's three. Martinez-Azorin recognize today's species as Stellarioides tenuifolia, based on morphological features including small flowers on dense and many-flowered inflorescences. These flowers later yield small capsular fruits. Stellarioides tenuifolia is a bulbous perennial found from the eastern cape of South Africa to tropical Africa. It has few to (more often) many linear leaves that begin to develop during the flowering stage. The flowers of Stellarioides tenuifolia are white to yellow with a green line along the centres of the tepals. This green line is visible on the flower buds of today's photo. As per the morphological features noted above, the flowers are held on a long-stemmed compact inflorescence, with the eventual capsular fruits bearing 5mm-long seeds. One unusual feature of Stellarioides tenuifolia cannot be seen from a photograph. This species has the lowest chromosome number known to-date in the plant world. Monica Ruffini Castiglione and Roberto Cremonini (PDF) explain that chromosome number is one of the most basic factors in reconstructing phylogenetic relationships. The lowest possible chromosome number is 1 (n=1, or 2n=2 if diploid), which occurs in only a couple species (e.g., male ants of Myrmecia pilosula). By contrast, the fern species Ophioglossum reticulatum has the highest number of chromosomes currently known at 2n=1440. Stellarioides tenuifolia is one of only six plant species known to have the second-lowest possible chromosome number, 2n=4. Castiglione and Cremonini explain that current theory posits that evolution favours ever-larger chromosome numbers, meaning that species with extremely low chromosome counts are "relicts conserving the karyotype of ancestral eukaryotes". [...]

Stapelia leendertziae


An entry from Tamara: I can always count on frequent contributor Bruce Brethauer (aka Glochidman@Flickr) to upload a photo of something strange and wonderful. Today's photos feature a close up view of a Stapelia leendertziae petal, as well as a photo of the entire flower. Thanks Bruce! Stapelia leendertziae has sapromyiophilous flowers--that is, its flowers are pollinated by flies. Sapromyiophilous flowers have evolved convergently in many families of flowering plants. They usually have large scent-emitting flowers that are coloured red or purple. These characteristics mimic the food and brood sites of carrion and dung flies. Johnson and Jürgens (2010) examined the scent compounds of sapromyiophilous flowering plants (and one fungus). They found that Stapelia leendertziae flowers emitted 31 different compounds, most of which contained sulfur. The compounds included dimethyl disulphide and dimethyl trisulphide, resulting in a scent that was remarkably similar to that emitted by dead rats (which end up being a different set of compounds than the more general "rotten meat"). Other plant species studied by Johnson and Jürgens emitted scents that also corresponded to fly-attractants, including dog faeces, horse dung, and the previously-mentioned rotten meat. Each species had its own specific set of scent compounds, these correlating with the types of flies that were seen visiting the flowers. In the case of Stapelia leendertziae, both blow flies (Calliphoridae) and flesh flies (Sarcophagidae) were observed visiting the flowers. Flies from both of those taxa are thought to consume and deposit their eggs (or hatched maggots, in the case of Sarcophagidae) on carrion. Stapelia leendertziae flowers are nicer to look at than to smell. As you can see from today's photo, the petals are dark red (Bruce Brethauer calls them liver-coloured), velvety, and rugose (wrinkled). The corolla forms a bell-shape that can reach 12 cm in length. The Flora of Zimbabwe cites bell-stapelia as one of the common names for the species. Most sources, however, use Leendertzi's carrion-flower. I suppose large bell flowers are an easier sell than the stench of rotting flesh. Stapelia leendertziae is commonly grown as a potted plant, but it is rare in the wild. It grows on rocky, shallow soil in Swaziland and northeastern South Africa. Since Stapelia pollinators can travel large distances to find individual flowering plants, members of this genus tend to be widely-scattered in the landscape. Stapelia leendertziae has dark green succulent stems that grow close to the ground. For the above reasons, finding carrion plant in its natural habitat is challenging unless it is in full flower. When in flower, simply follow the flies--and hope that you are heading towards a Staperlia leendertziae rather than a dead rat. [...]

Mentzelia packardiae


I've had a good rest from writing entries thanks to Tamara, but now that the school year is beginning, I feel I should start making my own contributions again. This late-May set of photographs is from the Leslie Gulch area of eastern Oregon, USA. I had long been interested in visiting the region, as it is both botanically and geologically fascinating. The area is known for its rock formations and volcanic history, but to botanists and plant enthusiasts it is also a special place. Dr. Barbara Ertter describes Leslie Gulch as a (relatively) recently-discovered botanical hotspot in her article Floristic Surprises in North America North of Mexico. Dr. Ertter, who studied in the area as an undergraduate, notes that "The unique ash-flow tuffs of Leslie Gulch have thus far yielded a total of 5 plant taxa new to science: Senecio ertterae [named in her honour] T.M. Barkley, Mentzelia packardiae Glad, Ivesia rhypara Ertter & Reveal, Artemisia packardiae J.W. Grimes & Ertter, and Phacelia lutea var. mackenziorum J.W. Grimes & P.L. Packard...". Several other rare taxa which had been previously recorded from nearby sites are also found in the area. I felt privileged to observe 3 of these 5 taxa while there, through my own explorations. Mentzelia packardiae, or Packard's stickleaf, is named after Dr. Patricia Packard, a professor at the College of Idaho and curator of the Harold M. Tucker Herbarium for thirty years. It was described and named by Judith B. Glad. The Center for Plant Conservation (CPC) has a factsheet about Mentzelia packardiae, which includes some details about Glad: "Judith Glad began her career as a Science Fiction writer. However, time and time again, her stories were rejected for being too romantic. Frustrated and looking for a change, she returned to school to pursue a Master's degree in Botany. While a graduate student at Oregon State University, Glad discovered two species unknown to science, Packard's mentzelia (Mentzelia packardiae) and Thompson's mentzelia (Mentzelia thompsonii). Glad returned to writing and is now both a successful romance novelist and an ecological consultant". A small (20-40cm) annual herbaceous species, Mentzelia packardiae is found on potassium-laden volcanic soils of the Leslie Gulch area primarily, with a disjunct population near Elko, Nevada. I observed the species at two separate sites in Leslie Gulch, both being bases of gravelly exposed slopes. This is seemingly the only type of site it will grow in; the Mentzelia packardiae factsheet (PDF) from the Oregon Department of Agriculture states, "occurs at the base of talus slopes along canyon walls in rocky, volcanic ash substrates". A portion of one of these talus slopes is displayed at the base of the landscape photo. One of these two sites was a research plot, clearly delineated by four rocks and rebar posts. It wasn't obvious to me whether the study site was for Packard's stickleaf or the associated species Senecio erterrae (also in the plot), but the stickleaf was growing in the dozens at the site while I only observed a few Senecio erterrae from the plot's edge (I was being observant for rattlesnakes, so fortunately didn't stumble my way into the plot and affect any research). [...]

Saponaria officinalis



There's something romantic about this photo of Saponaria officinalis growing in front of a weathered picket fence. I can almost imagine walking from my little cottage to the back garden to pick some common soapwort for laundry day. This would be once I had pulled the fresh-baked pies from the oven, of course. Thanks to tuvidaloca@Flickr for momentarily distracting me from my hectic modern life with this beautiful image.

Saponaria officinalis has many common names, including one that I include in my list of all-time favourites, bouncing bet. Not only is the name catchy, but it also evokes imagery about its uses and history. In Elizabethan England, laundry was done by scrubbing clothing against a washboard in a central plaza. The laundry women became known as "bouncing Elizabeths", or "bouncing bets", referring to their motions while scrubbing the clothing. Saponaria officinalis was compared to the bouncing bets for two reasons. One, the calyx and petals are said to bear a resemblance to the pinned up petticoats and backside of the washerwomen (not quite following that one, myself). Two, Saponaria officinalis has a high saponin content contributing to its historical use as a laundry detergent. According to Flora of North America, "the leaves of this species were gathered and either soaked or boiled in water, [with] the resulting liquid being used for washing as a liquid soap".

The Weed Science Society of America (click on Bouncingbet) has an article chronicling the geographic spread of this species. Originally from France and Germany, Saponaria officinalis was introduced to England by monks. It quickly became popular for its use as a soap and medicine. After the industrial revolution mechanized the textile industry, it was planted in masses as a source of detergent. When Europeans settled North America, bouncing bet was one of the species imported for its useful properties. It quickly became naturalized wherever the settlers went. It is now weedy in many parts of the world, but is considered by many to be particularly pretty (for a weed).

The pink to white flowers of Saponaria officinalis certainly add beauty to the cottage garden, roadside, or fallow field. Occasionally, the typically five-petaled flowers have double the amount of petals, a trait that has been encouraged in some cultivars including 'Flore Pleno'. Saponaria officinalis is a rhizomatous perennial that will quickly form wide clumps in open ground. It has upright stems that reach a height of up to 90 cm.

Medicago arborea



I was intrigued by Monceau@Flickr's photo of Medicago arborea fruits. Monceau describes these legumes as looking "like little collars". The other great image featured today was taken by Donald Hobern (aka dhobern@Flickr). It reveals why Medicago arborea, unlike most other members of its genus, is sometimes used ornamentally. Thank you Monceau and Donald!

Species of Medicago are commonly known as medicks. The genus is well-known for containing the agriculturally-important alfalfa (Medicago sativa). It contains over eighty other species, of which some are used for forage, medicine, or agricultural cover crops. Most species of Medicago are low creeping herbaceous plants, but Medicago arborea, or tree medick, is an exception. It is a large shrub that can reach a height of up to 4 meters. Tree medick has silvery-grey leaves composed of three leaflets that are often folded along their midrib. The inflorescences are terminal racemes bearing 4-8 orange-yellow flowers with butterfly-shaped corollas, with the flowers being the largest within the genus.

As Monceau has discovered, the seed pods of Medicago arborea are worthy of close examination. These fruits are flat and spiral-shaped, with the spiral having from .5 to 1.5 rotations or coils. Each legume contains 2-3 seeds. The most beautiful image that I have seen of a Medicago arborea legume is this hand-coloured micrograph made by the artist and professor Rob Kesseler. As explained in the Big Data exhibition catalogue (PDF, page 04), Kesseler uses a scanning electron microscope to capture a seed in exquisite detail, then applies colour to introduce "an artistic sensibility intended to create a sense of awe, with the dual purpose of extending knowledge within the respective fields of art and science".

Coffea arabica


I think about plants a lot. I notice them as I walk outside and of course I spent half of my week during the summer photographing and writing about plants for Botany Photo of the Day. Despite this, there is only one species that I think about each and every day: Coffea arabica. I have long appreciated the beauty of roasted coffee beans, but did not realize that the fruit are so attractive. Thank you Malcolm Manners (aka mmmavocado@Flickr) for this photo; it provides yet one more reason to love Coffea arabica. Today's photo shows the ripening drupes of Coffea arabica. These begin dark green, then gradually ripen through yellow to light red, and finally to a deep-cherry red. At this point, they are ready for harvesting (and the reason why the drupes are often called cherries). Picking the fruit at optimum ripeness is important to the quality of the coffee. Under-ripe drupes will make the coffee bitter, while drupes that have been left past the "cherry" stage will give the final product an acrid taste. As you can see, the fruit do not all mature at the same time. The best quality coffee comes from fruit that have been selectively harvested by hand, a laborious undertaking. Within the glowing red drupes lie two (or occasionally 1 or 3) seeds. These seeds are of course the coffee beans. They are arranged with their flat sides facing each other, wrapped in a parchment-like endocarp. Each seed has yet one more covering, the spermoderm, which in Coffea arabica is called the silver skin. The process of taking Coffea arabica fruit and transforming them into coffee beans for morning espressos is demanding. An FAO (Food and Agriculture Organization) document describes the steps involved in processing the fruit and curing the beans. Two species yield most of the world's coffee. Coffea arabica produces about 70% of the coffee consumed. The USA National Coffee Association describes the finicky growing environment required to produce high-quality coffee from Coffea arabica, including the fact that the coffee plants must be grown at elevations ranging from 600-1800 meters in mild climates that receive about 150 cm of yearly rainfall. Such sites tend to be steep, adding to the challenge of growing this species. Coffea canephora makes up the other roughly 30% of coffee grown for world markets. It contains more caffeine and is less pleasant-tasting than Coffea arabica. On the upside, it is more disease- and parasite-resistant and can grow in warmer climates, making it cheaper to cultivate than Arabica coffee. It is often used in instant coffees and blends. A third species, Coffea liberica, is grown commercially in small amounts. Coffea arabica is a small tree with horizontal, spreading branches. Its shiny evergreen leaves are elliptical and arranged oppositely, with a length of 5-20 cm. The intensely scented-of-jasmine flowers are found in axillary clusters (they arise at the junction of the stem and leaf). Weather has a great impact on Coffea arabica reproduction. The white-petaled flowers open simultaneously 8-12 days after a triggering rainfall. Weather at the time of flowering can have a large impact on the number of fruit produced, with sunny days tending to produce more fruit than is beneficial to long-term production. [...]

Monstera deliciosa


Some botanical names make me wonder about the botanists who dictated them, and this is one of those examples. Yes, Monstera deliciosa has monstrous leaves. And yes, its fruit, tasting of a mix of pineapple and banana, are indeed delicious. I like to think, however, that Frederik Michael Liebmann, the botanist who named this species, had a bit of a sense of humour. More likely Liebmann, a Danish botanist, never thought of what this name might sound like to an English speaker, thinking only that Monstera deliciosa sounded rather intellectual next to the Danish words uhyreI ("monster") and lækker ("delicious"). Today's photo of a Monstera deliciosa leaf was taken by Gwendolyn Stansbury (aka Gwendolyn Stansbury@Flickr). The photo of Monstera deliciosa's odd-looking fruit was taken by Barbara Dieu (aka beedieu@Flickr). Thank you Gwendolyn and Barbara! Monstera deliciosa is a tropical species, native to southern Mexico, Guatemala, and parts of Costa Rica and Panama. This species is often grown as a fast-growing, large house plant. It is a robust climbing vine that will reach up to 20 m in height if it is given the opportunity. Mature plants produce several inflorescences that emerge from the leaf axils. The Monstera deliciosa inflorescence consists of an erect spadix enclosed in a white, boat-shaped spathe. The corn cob-like spadix is covered in tiny white flowers. When pollinated, the spadix develops into a compound fruit that is covered in hexagonal scales. The fruit matures very slowly, taking as long as a full year to ripen. When ripe, the scales fall off, revealing creamy yellow fruit below. These fruit are tasty, but are the only part of the plant that is not toxic. High levels of oxalic acid found in the rest of the plant, including in unripe fruit, produce immediate blistering, irritation, and swelling in those who are unfortunate enough to consume it. The glossy-green, cordate leaves of Monstera deliciosa become perforated with holes as they mature, earning this species the common name of Swiss cheese plant. Upon seeing the fenestrated leaves of Swiss cheese plant, I immediately wondered how a plant species would benefit from such an unusual leaf shape. Christopher Muir, from Indiana University's Department of Biology, wondered the same thing. In the article How Did the Swiss Cheese Plant Get its Holes?, Muir asserted that the unpredictable sunflecks in a tropical rainforest canopy drive leaf fenestration. In order to understand Muir's hypothesis, one must first understand the role that variance in fitness has on genetic selection. Negative fluctuations in fitness produce a greater effect than positive fluctuations, so (other factors aside) individuals with the lowest amount of variance are the most successful (see Why the Variance in Fitness Matters). Although fenestrated leaves don't harvest a greater amount of light from sunflecks on average, Muir shows that this shape decreases the amount of variance in the levels of sunlight reaching Monstera leaves. It is better for a Monstera leaf to receive a single patch of sunlight over two days than it is for the same leaf to receive a patch of light double the size one day, and no light the next. [...]

Pycnoporus coccineus


Frequent Botany Photo of the Day contributor Andreas Lambrianides (aka andreas lambrianides@Flickr) took this photo of a fruiting [...]

Rhododendron falconeri



Type in the word "rhododendron" in an image search, and countless beautiful photos of vibrantly-coloured blooms will appear. The same is true when searching through the Botany Photo of the Day archives: Rhododendron 'Cornubia', Rhododendron moupinense, and Rhododendron periclymenoides represent but a few of the beautiful rhododendron flowers that we have featured.

UBC Botanical Garden has a fabulous collection of rhododendrons from Asia and North America. Like many of our visitors, I am amazed at the beauty and diversity of flower forms possessed by this remarkable genus. As I wander the narrow, shaded pathways of the David C. Lam Asian Garden, however, I am just as often struck by the beauty of the rhododendron leaves that I encounter and by the way that these leaves play with the Garden's ambiance. The thick, substantial rhododendron leaves allow brief shafts of light through the canopy, shining a spotlight on random botanical objects that would otherwise pass unnoticed: here, a spot of light touches on the threads of last-year's maple leaf; there, a tiny tip of a pipevine corkscrews brightly against a dark background. Tiny botanical beauties go unnoticed against a wall of fuchsia flowers, but shine against the restrained backdrop of rhododendron leaves.

Of rhododendron leaves, I find those with contrasting indumentum the most captivating. Indumentum is the coating of extremely fine hairs that can be found on the lower surface of the leaves of many rhododendron species, including those of Rhododendron falconeri. Today's photo shows the underside of one of these leaves, which in its entirety measures about 20 cm long and 8 cm wide, is elliptic in shape, and is held on a long petiole (stalk). I am entranced by the pinnate pattern formed by this leaf's strong veins and by the dusting of felt-like, rusty hairs.

The upper surfaces of Rhododendron falconeri leaves are dark green and have been described as curiously wrinkled. A very light coating of hairs, termed tomentum, coats these surfaces and may prevent insect herbivory.

Parameconopsis cambrica



I have been reading about European poppies in the book Weeds: In Defense of Nature's Most Unloved Plants, so Mats Ellting's (aka mellting@Flickr) recently-posted photo of Parameconopsis cambrica caught my attention. Although the book doesn't cover Welsh poppy specifically (the examples given are all in the genus Papaver, but more about that below), it shares many characteristics with the poppies that do get included, such as plentiful seeds that persist in the soil for a surprisingly long time. Thank you Mats, for posting this gorgeous photo!

Well over 250 years ago, Linnaeus observed that Welsh poppy was similar to the other members of the Papaver species found throughout Europe, and he named Welsh poppy Papaver cambricum. In 1814, Viguer renamed the species Meconopsis cambricum, founding the genus Meconopsis on the basis that its members have a distinct style, rather than a disc-shaped stigma that lacks a style and instead attaches directly to the ovary. Since then, all poppies with styles have been labelled as Meconopsis. The genus has grown to include about 50 accepted species.

Gardeners have always noticed that Welsh poppy is the black sheep of the Meconopsis (or, the yellow sheep, I suppose). The large, Himalayan blue poppies, such as Meconopsis baileyi, are quite challenging to grow whereas Welsh poppies grow under most conditions and even tend to become weedy. Most members of Meconopsis are monocarpic, that is, they die once setting seed, while Welsh poppies perennially produce fruit. All of the Meconopsis come from Asia, while the Welsh poppy is from Europe. Recently, genetic studies proved that Linnaeus (and all of those gardeners) were onto something all along. A study published in the New Journal of Botany asserted that other members of the Meconopsis evolved styles independently of the Welsh poppy, and that its closest relatives lie in the genus Papaver.

Changing Meconopsis cambrica to better reflect its uniqueness, however, was easier said than done. Since it was the founding member of its genus, the Welsh poppy should technically retain the genus name Meconopsis, and all other members of the genus should be moved elsewhere. This proved problematic, as Meconopsis is a well-known genus and many of its members are celebrated horticulturally. Changing all of these species into a new genus would be disruptive and costly to many people. A more palatable solution was proposed by Christopher Grey-Wilson, who suggested the name Meconopsis be retained for all of the Asiatic species, and that a new generic name be created for the Welsh poppy, Parameconopsis cambrica. A full account of Grey-Wilson's reasoning can be found in his beautiful and informative book, The Genus Meconopsis: Blue Poppies and their Relatives (2014).

Eryngium leavenworthii



Somehow, I have managed to go through life without once noticing a sea holly. When I saw Don McClane's perfectly-captured image of Eryngium leavenworthii, I immediately thought, "what is that, and how can I get one!?". It turns out species of Eryngium have long been prized by gardeners. Seeds of many species, including Eryngium leavenworthii, are readily available. Thanks Don for introducing me to the beautiful sea hollies!

Eryngium leavenworthii is native to south central USA. It is found on limestone or chalky soils of prairies, open woodlands, and roadsides. It is an annual or short-lived perennial species that reaches a height of nearly a meter. Eryngium leavenworthii's claim to fame is its brilliant purple colour. The terminal flower heads are composed of minute purple flowers and bracts (these turn purple as the flowers open). The stamens are electric blue, and the pineapple-shaped flower heads are subtended by an involucre of brightly-coloured lobed spiny bracts. The tips of the flower heads bear a tuft of small spiny leaves that deepen to purple as the flower enters anthesis.

This species is popular with native plant gardeners in its range. It is drought-tolerant and readily grown from seed. Michael McDowell, who blogs about his Texas native garden, suggests planting this Eryngium behind other prairie plants such as little bluestem (Schizachyrium scoparium) since its stem and leaves can get scraggly. Being an annual, it will likely grow in most climates, but will require extra attention in areas with cool temperatures or high rainfall. Plant it in free-draining, slightly alkaline soils for best results. Soils with too much fertility will cause Eryngium leavenworthii to grow leggy and for the leaves to overwhelm the floral display. If you can grow tomatoes successfully, Eryngium leavenworthii will likely work well for you. The seeds should be sown directly in the autumn or after the last frost in early spring.

Epilobium hirsutum



Thank you to marianne@Flickr, for capturing the riotous purple of Epilobium hirsutum in bloom. This photo gives a good indication of the density, uniformity, and beauty of a typical patch of Epilobium hirsutum.

Epilobium hirsutum is an herbaceous species that reaches 1 to 1.5 meters in height. It has woolly leaves and stems, hence the name hirsutum (Latin for hairy). The common name for this species, great willow-herb, is inspired by its long, narrow leaves that are similar in appearance to the leaves of willow species (Salix spp.). Epilobium hirsutum produces many showy flowers that are purple and bell-shaped. It has long white stigmas that ripen at the same time as the anthers, making the flowers capable of self-pollination. Before resorting to self-pollination, Epilobium hirsutum flowers hold their stigmas prominently, so that an insect may cross-pollinate them. Should this fail to happen, the stigma on the fading flower curls backwards to touch the ripe pollen held on the stamens. These flowers then form long narrow capsules that contain small seeds attached to long white hairs.

Great willow-herb is native to Eurasia, but is now a common weed around the world. It forms dense, monotypic stands in wetlands and waterways. It is associated with another wetland species, purple loosestrife (Lythrum salicaria). Epilobium hirsutum and Lythrum salicaria strike a seasonal balance - in autumn, the shorter days and colder temperatures favour Epilobium hirsutum while in spring Lythrum salicaria grows more quickly, making up for lost ground. Together, these two species form bright purple, colourful flower displays. Both Epilobium hirsutum and Lythrum salicaria were originally planted as ornamental garden species. Despite their beauty, they should not be planted outside of their native range, as both can aggressively crowd out other wetland species.

Achillea millefolium


Today's photo features one of my favourite plants of all time - Achillea millefolium, or yarrow. There are many excellent photos of yarrow available online, but I particularly like the contrast between the green and white that Randi Hausken (aka randihausken@Flickr) has captured in today's image. To call Achillea millefolium a species is incorrect. Achillea millefolium is a species complex, or aggregate, that consists of a set of species that are closely related. The members of the Achillea millefolium aggregate have a combination of different ploidy levels and natural hybridization. The relationships between the members of the aggregate are difficult to reconstruct. Guo, Saukel and Ehrendorfer (2008)(pdf) recount some of the attempts to make sense of the Achillea millefolium aggregate, which include placing all members into one giant species, or conversely, breaking the aggregate down into 40+ micro-species. One way of sorting the Achillea millefolium aggregate is by ploidy level (number of sets of chromosomes in a cell). The diploid (2 sets of chromosomes) taxa are limited to distinct areas in Eurasia and are less variable than the others. Achillea millefolium also come as tetraploids (4x), hexaploids (6x), and octoploids (8x). These species groups are far more variable and have an extensive northern hemispheric distribution. They are found in a wide variety of habitats from deserts to sea coasts, lawns and talus slopes. The diversity of forms and locations that yarrow occupies is one of the reasons that I love this plant so much. In the period of one day, I can see tall pink yarrow cultivars that I have planted in my garden, the dainty fern-like foliage of yarrow growing weedily in lawns, scruffy yarrow growing along the roadside, and short-stemmed yarrow growing wild along an alpine trail. Although I will likely never understand the evolutionary sequence of these members of the Achillea millefolium aggregate, I can still make use of any of them if I am feeling ill or have been hurt. As a child, my mother would make a tea of yarrow flowers, amply sweetened with honey, anytime that I had a cold or flu. A review on phytochemistry and medicinal properties of the genus Achillea lists many medicinal properties for yarrow, including its use in treating wounds, ulcers, and diabetes. I imagine that most of the Botany Photo of the Day readers in the northern hemisphere are just as intimately familiar with Achillea millefolium as I am. Those of you in the south are likely wishing I had provided a description of yarrow 2 paragraphs ago! Here it is: [...]

Angophora subvelutina



Today's photo shows a gnarly Angophora subvelutina photographed in its natural range of eastern Australia. Thank you to dustaway@Flickr, who captured a sense of movement and loneliness in the Australian savannah.

Angophora is closely related to Corymbia and Eucalyptus, all three of which are referred to as eucalypts. The distinguishing characteristics of Angophora are opposite leaves and fruit with sharp ribs (as opposed to Eucalyptus' generally smooth fruit). Angophora fruit also lacks an operculum, or bud cap. The name Angophora is composed of the Greek words for goblet (angeion) and carry (phoreo), in reference to the cup-shaped fruit.

Angophora subvelutina is locally abundant in the eastern parts of the Australian states of New South Wales and Queensland. It prefers fertile soils, making it an indicator of good farmland. It is also known as broad-leaved apple (the term apple is used by Australians to refer to any Angophora species). This medium-sized tree has twisted and gnarled branches with flaky, brittle bark. Not shown in today's photo is the lignotuber - a woody swelling of the root crown that provides insurance against disturbance such as fire. If the upper parts of Angophora subvelutina are cut or burnt, it resprouts from buds within the swollen crown. The lignotuber stores carbohydrates that may make a critical difference should the tree lose all of its photosynthetic parts. Angophora subvelutina also employs epicormic buds as part of its fire-survival strategy. These buds within the bark of trees are explained further in a previous post featuring Eucalyptus coccifera.

Mature Angophora subvelutina leaves are blue-grey to dark green, while new leaves are rosy pink. The size, shape, and length of petiole of the leaves varies considerably. The colour of the new leaves, coupled with new growth that is covered in scattered long red hairs gives this species another of its common names, red apple. The inflorescence is prolific. Loose corymbs of small white to cream flowers are held at the tips of branches. These abundant flowers are an important source of honey, and also provide nectar for butterflies and the Queensland blossom bat (Syconycteris australis).

Physocarpus opulifolius 'Monlo'


Today's photo features a purple-leaved cultivar of ninebark, Physocarpus opulifolius 'Monlo'. This photo was taken by Anne Elliott (aka annkelliott@Flickr) at Olds College botanic Gardens and Wetlands in Alberta, Canada. Thanks for sharing, Anne! The wild, eastern North American Physocarpus opulifolius is an attractive species in its own right. It provides interest in the garden nearly any time of year. The tall, arching stems form a vase-shaped bush that can be used in borders, hedges, or as a specimen plant. Abundant, fluffy corymbs of white flowers in late summer are followed by dark glossy red fruits that persist into late autumn (fading to a rosy tan). In winter, the stems take the spotlight. The bark exfoliates in narrow strips, revealing layers of different hues that inspire this species' common name. The cultivar 'Monlo' takes the ornamental merits of Physocarpus opulifolius to the next level. The selection was discovered growing in a field along with 120000 other Physocarpus opulifolius seedlings at Kordes Nursery in Germany. One seedling had unusual red foliage; its potential was recognized by the nursery owners, who designated it as the cultivar 'Monlo'. Physocarpus opulifolius 'Monlo' offers all of the same gardening qualities as its native counterpart, but in addition boasts deep-burgundy foliage. As you can see from today's photo, the crinkled leaves look particularly stunning when contrasted with this cultivar's pink-tinged flowers or red fruits. The combination of these qualities has earned Physocarpus opulifolius 'Monlo' the Royal Horticultural Society's (RHS) Award of Garden Merit. If you are seeking this cultivar for your garden, it is typically marketed under the registered trademark Diabolo® (though many sources incorrectly treat the trademark name as the cultivar name, or sometimes drop the first "o" from the name). As a native plant enthusiast, I feel an unjustified sense of pride when a species from my own continent gains international acclaim. It's nice to know that plants that are (at least) similar to species supporting wild North American ecosystems are finding their way into gardens worldwide. Still, a number of studies have indicated that native plant species result in higher insect diversity than exotic plantings (see Wilde, Gandhi and Colson 2014). I wondered, however, whether a Physocarpus opulifolius 'Monlo' planted within the wild ninebark's range could contribute to local ecosystems as much as the native species would. Two entomologists from the University of Minnesota, Emily Tenczar and Vera Krischik, attempted to answer this question. They tested which ninebark plants that specialist ninebark beetles (Calligrapha spiraeae) preferred to eat and lay their eggs on. These beetles were presented with the native Physocarpus opulifolius as well as its cultivars 'Monlo' and 'Dart's Gold'. The ninebark beetles seemed indifferent to whether they were making use of the native species or 'Dart's Gold', but avoided laying their eggs or eating the cultivar 'Monlo'. At least for this species of insect, it didn't matter whether a plant was wild-grown or cultivated. Instead, the species or cultivar's specific characteristics were what made the difference. Tenczar and Krischik posit that the high levels of foliar anthocyanins found in the cultivar 'Monlo' were the likely reason that the beetles favoured the other ninebarks. How does a gardener considering pollinators and wildlife decide whether to plant native species or cultivars (and if cultivars, which ones?)? The article, Native Cultivars - Good, Bad, and Ugly by Vincent Vizachero provides a straightforward answer. The article suggests staying awa[...]