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

Sep 17, 2014: Juniperus maritima

Bent, but not broken, this seaside juniper is one of a small population of at most a couple dozen individuals growing in Washington's Deception Pass State Park. These particular plants persisting against wind and saltspray form an atypical ecotype, as no other population is known to grow in this form and in a sand dune habitat. Typically, Juniperus maritima is an upright tree of the rocky margins of water bodies. The largest two known populations of several hundred plants each are in lands bordering Washington's Puget Sound (another common name is Puget Sound juniper), but its range extends northward into lands adjacent to British Columbia's Strait of Georgia. If geography is to be incorporated into a common name, a more inclusive moniker could be argued (e.g., Salish Sea juniper).

Juniperus maritima was scientifically described and published in 2007 (with a type specimen collected from Brentwood Bay, British Columbia). It may be hard to believe that a tree species near large urban areas of North America could escape the notice of botanists until 2007, but part of the reason for this is its extremely close resemblance to the Rocky Mountain juniper, Juniperus scopulorum. To be fair, Arthur Lee Jacobson (in his excellent write-up about Juniperus maritima) points out that the eminent botanist Leo Hitchcock wrote (in 1969): "Plants from the islands of Puget Sound appear to differ somewhat from those [Juniperus scopulorum] east of the Cascades in having the juvenile foliage longer-persistent and in producing cones [berries] that are less fleshy and rather consistently 1-seeded and it is believed not improbable that they will prove to constitute a distinctive race of the species." It did take nearly 4 decades for that distinctiveness to be recognized scientifically, with convincing data coming from chemistry (terpenoid analysis) and genetics (ITS sequences).

More on the subtle physical differences between Juniperus maritima and Juniperus scopulorum can be gleaned from Botanical Electronic News #387 (January 17, 2008): Juniperus maritima, the seaside juniper, a new species from Puget Sound and Georgia Strait, North America. The original paper is available as well: Adams, R.P. 2007. Juniperus maritima, the seaside juniper, a new species from Puget Sound, North America (PDF). Phytologia 89(3):263-283). Additional photographs of this species can be seen via E-Flora BC (Juniperus maritima) or the Burke Museum Herbarium's image collection: Juniperus maritima.

Sep 12, 2014: Ipomoea purpurea

Ipomoea purpurea

Today we have an entry written by Taisha prior to her departure. Taisha wrote:

Ipomoea purpurea, or the common morning glory, is photographed here by Hugh Nourse (aka Hugh and Carol Nourse@Flickr). This photo was taken last month along the Blue Ridge Parkway in North Carolina. Many thanks for sharing, Hugh!

The bindweed or morning-glory family consists of over 1600 species, including Ipomoea purpurea. This species is an annual vine native to Mexico and Central America, but it has established elsewhere (e.g., in much of the USA and parts of Canada). This species is cultivated worldwide as an ornamental due to its large and showy trumpet-shaped flowers. The Mexican populations are monomorphic for flower colour (having only purple flowers), whereas the introduced populations in the USA are highly polymorphic for flower colour, ranging from white to pink to red and purple. Common morning glory possesses a number of weedy traits such as rapid and aggressive growth, high seed output, and extended seed dormancy in soil seed banks. Indeed, this opportunistic colonizer of disturbed sites is now regarded as a noxious weed in the southeastern United States.

Little is known about the timing and geographic origin of US populations. One hypothesis is that this species was introduced into the United States with maize cultivation ~4000 years ago and subsequently dispersed (called the "Maize migration hypothesis"). Another hypothesis is that it was introduced through Europe after European contact with the New World (termed the "European migration hypothesis"). In this scenario, Spanish explorers are suspected of collecting seeds of Ipomoea purpurea in its native range, sending them to Europe to plant in monastery gardens, and then later being introduced to colonial North America (north of Mexico) around 1700.

In a study by Fang et al., the researchers examined data from 11 loci and 30 Ipomoea purpurea accessions from the native range of the species in Central and Southern Mexico, and 8 accessions from the southeastern USA in an attempt to infer the precise Mexican origins of the southeastern USA populations.

Fang et al. assert that Ipomoea purpurea made its way to southeastern USA via Europe. They support the European migration hypothesis due to the low genetic diversity of the southeastern USA population compared to Mexican populations. This suggests a strong founder effect consistent with multiple founder events (e.g. Mexico to Europe and Europe to southeast USA). This is paired with a severe population bottleneck, which contrasts with the maize diversity in the USA. If common morning glory did migrate with maize after all, one would expect a larger diversity, given the shared demographic history of morning glory and maize. Fang et al. attribute the higher levels of flower colour polymorphisms in the southeastern USA compared to native Mexican populations to the desire for diverse flower colour, consistent with the introduction of this species from Europe to the USA for its horticultural appeal.

As for the origins of the southeastern USA populations, the researchers suggest the western Mexican populations (rather than the southern or eastern). They propose this origin based on their genetic assignment analysis, haplotype composition, and the degree of shared polymorphism. They note that the eastern Mexican populations likely did contribute genetically, but the western populations contribute in large part for three reasons. First, the western Mexican population has the highest diversity and thus a larger effective population size. Secondly, based on the European migration hypothesis, the early trade routes from Mexico to Spain were from the Valley of Mexico eastwards through Xalapa and onto the port of Veracruz. Lastly, they point out that the domestication of maize was ~9000 years ago in the Balsas River Valley, which is ~300km southwest of the Western population. If this were the case, then one would assume the colour variants of Ipomoea purpurea would have spread through Mexico and Central America along with maize culture, rather than the monomorphic purple form.

The researchers end by noting that although it is likely that Ipomoea purpurea first migrated to Europe before being introduced to the southeastern USA, there was substantial trade in the Aztec and earlier eras between the Valley of Mexico and regions to the east and south of Mexico, allowing for seed to be traded before the arrival of Europeans. Also, they mention that the accessions from the Valley of Mexico that show high similarity to the southeastern USA populations could have accompanied modern travelers or been reintroduced back to Mexico to be planted in gardens with likely escapes (see: Fang, Z. et al. (2013). Tracing the geographic origins of weedy Ipomoea purpurea in the Southeastern United States. Journal of Heredity. doi: 10.1093/jhred/est046).

Sep 10, 2014: Ficus platypoda

Ficus platypoda

A thank you to Lorraine P. (aka Boobook48@Flickr) for sharing this photograph from Caranbirini Conservation Reserve in the Northern Territory of Australia (original image via the Botany Photo of the Day Flickr Pool). To see more photographs from the area, do visit Lorraine's Flickr site or (for more of her Australian travels), see her blog, Bushranger.

Ficus platypoda (platy- meaning "broad" and -poda meaning "foot") is commonly known as desert fig or rock fig. This species is broadly distributed in the northern half of Australia, but seems most often associated with dry, rocky habitats of central and northern Australia (as illustrated). Lorraine notes that the roots of Ficus platypoda "...swell with water and the process can create enough pressure to crack the rock. Over hundreds of years the plants contribute to the erosion of the sandstone to create the beautiful beehive shapes in the reserve". To see these shapes, we again turn to Lorraine's photos: Caranbirini Conservation Reserve photo 1 and photo 2.

This shrub or small tree (to 9m) takes well to cultivation. Given its ability to grow in rock, it is used for drought-resistant plantings. It also accepts pruning well, either as a specimen tree or a bonsai.

Botany resource link: Eric Hunt sent the following news story: Desert Plant Derives Up To 90% Of Water-Intake From Gypsum Rock (via Neomatica). Please ignore that the linked article is illustrated with the wrong species. Instead, learn that plant physiologists from the Instituto Pirenaico de Ecología in Spain have demonstrated that at least one species of vascular plant (Helianthemum squamatum, Cistaceae) is now known to be able to extract water directly from the crystalline matrix of gypsum.

Sep 5, 2014: Sanguinaria canadensis

Sanguinaria canadensis

The start of the school year is always a busy time, so apologies for the lack of postings.

While photographing this past April for the Vancouver Trees app we are nearing completion on (oh, so very near), I took a break from woody plants and played with a patch of bloodroot at VanDusen Botanical Garden. The leaves of Maianthemum (canadense?) briefly provided a spotlit background. When rendered out-of-focus through the use of a large aperture, the overall impression to me is of a flower and the Northern Lights.

The eastern and central North American Sanguinaria canadensis has been featured twice previously on BPotD: the cultivar Sanguinaria canadensis f. multiplex 'Plena' (the 14th-ever BPotD entry); and the flowers of the species from above: Sanguinaria canadensis.

Bloodroot, as you might guess, has roots and rhizomes with a reddish juice (scroll down on this page for photos). This liquid contains a number of alkaloids, primarily sanguinarine. While toxic with sufficient doses (one of the symptoms being "tormenting thirst"), bloodroot has a long history in traditional and contemporary medicines. These are detailed in Agriculture and Agri-food Canada's Medicinal Crops factsheet for the species, with indigenous uses primarily being for the treatment of respiratory or throat and mouth ailments. These uses have continued into contemporary medicines, and sanguinarine can be an ingredient in cough syrups, expectorants and anti-gingivitis rinses & toothpastes.

For cultivation and propagation details, please see the Alpine Garden Society's site: Sanguinaria canadensis. Gardening details can also be found on the Missouri Botanical Garden's Gardening Help site: bloodroot.

Aug 29, 2014: Themeda triandra

Taisha completes the series on South African plants and biomes with this entry. It is also her last official day as a work-learn student with Botany Photo of the Day, though there are about a half-dozen other entries she has written that will be posted while the new students learn the ropes. Thank you, Taisha. She writes:

Today we feature the grasslands biome of South Africa with photographs of Themeda triandra, which is known as rooigrass in Afrikaans ("red grass"). These images (image 1| image 2) were uploaded to the Botany Photo of the Day Flickr Pool by Marie Viljoen@Flickr. The first image was originally posted on Marie's blog, where she later posted a poem about Themeda triandra by South African poet, Antjie Krog. Thanks again, Marie!

The grasslands, also known locally as Grassveld, is the largest biome within South Africa. It is found mainly on the high central plateau of South Africa as well as the inland areas of the Eastern Cape. This biome neighbours the savanna, thicket, and Nama Karoo biomes. This region is relatively flat, though it can vary between sea level and 2850m elevation. The semi-arid to arid grasslands have varying temperatures, with frost being common. Precipitation ranges between 600-1000 mm, with rainfall decreasing westward. The grassland occurs on a variety of soils from humic clays to poorly structured sands.

A single vegetative layer of grasses dominates the grasslands, although other species such as bulbs occur. There are two categories of grassland: sweet veld and sour veld. Sweet grasses occur on the semi-arid regions of the Eastern Cape in eutrophic soils, while the sour grasses can be found in the higher rainfall regions of Drakensberg on acidic soils.

Themeda triandra is a tufted C4-photosynthesis perennial grass occurring widely across parts of Africa, Australia, and Asia. In South Africa, Themeda can occur in the savanna biome, but is primarily found in the grassland biome in regions with rainfall between 500-950 mm and at elevations of sea level-1800m. When young, this grass is a green to blue-green colour tinged pink. It then turns red with age. Rooigrass at higher altitudes tends to be shorter and darker compared to plants at lower elevations. The spikes flower from October to July. Flowers may or may not long black or white hairs. The awned spikelets hang from clusters and are surrounded by reddish brown leaf-like spathes or bracts. Rooigrass does not vegetatively spread long distances, so it is instead an obligate seeder. The long hygroscopic awns twirl when wet, driving the barbed seeds into the ground. There, they will germinate if there is a layer of litter or pioneer plants. This species is noted to be resistant to fire, with resistance increasing if the site is not overgrazed and burnt at regular intervals to allow for regeneration.

Aug 28, 2014: Welwitschia mirabilis

The second-last in the plants and biomes of South Africa series is featured today. Taisha writes:

Today, we take a slight detour from South Africa, as this species is not present in the country. Welwitschia is found only in the Namib Desert of Namibia. However, the Namib Desert slightly extends into South Africa where it forms the country's sole area of desert biome. The Namib Desert is one of the smallest and oldest deserts in the world. I chose Welwitschia as it has not been featured on Botany Photo of the Day before and it was not easy to find a plant species in the Botany Photo of the Day Flickr Pool to represent this biome. Still, this species is an interesting representative for the desert. Daniel contributed these photographs of Welwitschia mirabilis from Huntington Botanical Garden.

As implied above, the desert biome occurs in only a small part of northwestern South Africa, primarily the Springbokvlakte area of the Richtersveld. The altitude is between 600 and 1600 m, which results in a slightly cooler climate than other true deserts (though it remains more climatically extreme than the succulent Karoo and the Nama-Karoo biomes). Temperatures can be hot, up to 45°C. Similarly extreme, temperatures can drop over 20°C from day to night. Winter temperatures can be as low as -12°C. Fog from the nearby Atlantic Ocean accounts for much of the precipitation, although there is some variable summer rainfall (~10-80mm annually). True deserts are largely sandy with low organic material in their soils.

The vegetation within the desert biome is typically annual grasses and other plants. After a season with rarely abundant rains, short annual grasses may grow, whereas in most years the annual plants persist as seeds. Some perennials may survive, particularly in areas associated with local concentrations of water.

Welwitschia mirabilis is a monotypic species of the Welwitschiaceae under the plant Division Gnetophyta--a small group of seed plants that have intermediate characteristics between gymnosperms and angiosperms. The oldest specimens of Welwitschia in the Namib Desert are thought to be more than 1500 years old, and recent fossil evidence suggest that Welwitschia was present during the Cretaceous (~112 million years ago). Some photos of the plant in habitat are available via Wikimedia Commons: the biggest known plant and a couple plants in the landscape.

This dioecious (male and female individual plants; male and female cones are shown above) evergreen species has a woody unbranched stem that is shaped like an inverted cone. The stem is surrounded by a bi-lobed crown of green photosynthetic tissue. There are only two opposite, persistent, ribbon-like leaves that grow continuously from a basal meristem and die off at their tips over time. Unique among all extant plant species, after the first two leaves form, the terminal bud dies and the apical meristematic activity is transferred to the periphery and base of the leaves. In other words, it has ever-growing persistent leaves, with the leaf ends being the oldest part of the leaf.

Aug 25, 2014: Bauhinia galpinii

Bauhinia galpinii

Here is entry number six in Taisha's South African plants and biomes series. She writes:

Bauhinia galpinii, known as Pride of the Cape or Pride of De Kaap, is featured today as part of the savanna biome. Even though the name may suggest it is from the Cape (de kaap= cape), it is actually named after the De Kaap valley in the northeastern region of South Africa. This 2007 photo was taken by frequent BPotD contributor, Bart Wursten (aka zimbart@Flickr), in Manica, Mozambique. In addition to South Africa and Mozambique, the species is also present in Zimbabwe. Thanks for sharing, Bart!

The savanna biome spans a large area over the lowveld and Kalahari regions of South Africa. Elevation ranges between sea-level and 2000 m. Summers are very hot and rainy in this region, with temperatures anywhere between 12 and 39°C. This is followed by a cooler dry season where temperatures range from 0-32°C. Annual rainfall varies from 235mm-1000mm in the biome, and some parts of it may be frost-free while others can have up to 120 days of frost/year. Many of the major soil types (PDF) are represented in the region, though soils are usually porous, quick-draining, and with a thin layer of humus.

The savanna has a distinguishable grass-dominated ground layer accompanied by the different densities of woody shrubs and trees (shrubs may be the most prolific plants in overgrazed areas). C4 grasses form much of the grass layer where there is a hot growing season (C4 photosynthesis is best-suited for heat), while C3 grasses tend to be in the majority in cooler, wetter parts of the biome. Many plant species are adapted to survive fires, and most will resprout from stem bases even after severe burning.

Bauhinia galpinii is a fabaceous shrub with two-lobed leaves and bright red-orange flowers. This species is traditionally used medicinally by the Venda (or vhaVenda) people of the Limpopo province. In Mahwasane et al.'s survey of indigenous knowledge on medicinal plants used by the traditional healers of Limpopo's Lwamondo area, the roots of Bauhinia galpinii are boiled and the mixture drunk to treat stomach worms or to improve sexual performance. They also add that the concoction can be used to make a soft porridge for stomach pains. The researchers further mention that other studies have claimed that this species is used for treating diarrhea and infertility (bark and leaves), for infertility using the roots, or for amenorrhea (seeds). Traditional healers (herbalists) of the vhaVenda use up to 16 species of herbs, trees, or shrubs within seven families for medicinal purposes. Those from the Fabaceae are used most frequently; other families represented were Annonaceae, Asteraceae, Ebenaceae, Orobanchaceae, Oxalidaceae, and Verbenaceae. Different plant parts are collected from the medicinal species, most often the roots (also the leaves, bark, flowers, or whole plant), and diversely prepared for treating the above illnesses as well as others, including stomach ailments, dysmenorrhoea and oedema (see: Mahwasane, S., L. Middleton, and N. Baoduo. (2013). An ethnobotanical survey of indigenous knowledge on medicinal plants used by the traditional healers of the Lwamondo area, Limpopo province, South Africa. South African Journal of Botany. 88:69-75).

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