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Results tagged “written by cora”

Dec 19, 2014: Ophrys umbilicata subsp. flavomarginata

Ophrys umbilicata subsp. flavomarginata

BPotD work-learn student Cora den Hartigh wrote today's entry:

Thank you to Andreas Lambrianides (andreas lambrianides@Flickr) for this "happy" flower from the Akamas Peninsula, Pafos, Cyprus! These orchids are rare to find outside of the grasslands of Cyprus, but they can be found in similar habitats in Israel and Jordan.

Ophrys umbilicata subsp. flavomarginata is a delightful species of orchid that is easily anthropomorphized. Just look at those cute fuzzy (hirsute) arms (actually, lateral lobes)! Otherwise known as the yellow-lobed bee orchid, this species is closely related to several other Ophrys spp. that mimic insects, two of which have been previously featured on BPotD: see the gorgeous Ophyrs bombyliflora for a discussion of plant trickery, or the sly Ophrys tenthredinifera.

Co-evolution has exquisitely tailored orchids to appeal to specific pollinators, predicating a radiance of flourishing diversity and interdependence. There are orchids that smell like chocolate or mushrooms or powerful head-spinning perfumes. There are orchids that look like flying ducks (Caleana major) and monkey faces (Dracula simia, among others). There are rare species of blue orchids or sneaky parasitic orchids - they are in fact so diverse that it is possible to find orchids in nearly every biome! One of my favourite genera is Catasetum, whose species fire pollen so forcibly when the seta of plants are brushed that the pollinators are knocked back into the air!

Another orchid story: in 1798, Darwin received a curious specimen of Angraecum sesquipedale (Christmas star orchid) in the mail from a naturalist friend exploring in Madagascar which was possessed of a remarkably long nectar spur. What could possibly pollinate such a flower? Darwin postulated some insect might be uniquely adapted to this orchid by way of a similarly long proboscis. It was not until 1903, a century later, that a moth (Xanthopan morgani praedicta) was discovered fitting Darwin's description. The orchid and moth are celebrated examples of Darwin's evolutionary theories and the fine tailoring of biological relationships. You can check out a video of the moth in action. Notice that Angraecum sesquipedale is white; pollinated by a nocturnal insect, the plant presumably had no need to evolve colourful pigments for attracting pollinators, unlike today's subject.

Speaking of orchid diversity, I spent last summer working at a botanical garden that had no less than 3000 species of orchid at any given time. The collection had been gifted from a private donor in Vancouver and was housed in three misty greenhouses that were positively intoxicating! If you visit Edmonton, consider checking out the Muttart Conservatory. Alternatively, you can always take a moment to peruse the web site of the Orchid Species Preservation Foundation!

Dec 12, 2014: Dictyonema huaorani

Dictyonema huaorani

BPotD work-learn student Cora den Hartigh is the author of today's entry. She writes:

Dictyonema huaorani is a lichen I have been researching quite a lot this semester. For a directed studies project, I chose to investigate hallucinogenic lichens--a hybrid between popular lichenology and scientific enquiry. It was a lot more difficult than anticipated, but I finally turned in a short book, over a week late! That's just how it goes sometimes. Nevertheless, I contacted Michaela Schmull at the Harvard Herbarium, who was able to forward me this magnificent scan. Now I can share the story here!

This is a scan of the thallus, or vegetative structure, of Dictyonema huaorani. This specimen was collected in 1981 by Wade Davis and Jim Yost, two explorers in eastern Amazonian Ecuador conducting ethnobotanical research with the Waorani people. Yost had heard rumours of this lichen for seven years before finally locating this individual. To date, this is still the only known specimen in existence. As you can see by the label, this lichen was found growing on rotting wood near the confluence of the Quiwado and Tiwaneo rivers in Napo state. Known as nɇnɇndapɇ by the Waorani, the lichen has been used by "bad" shamans to curse others and also been noted to cause severe headaches. It was reputed to potentially have hallucinogenic properties.

The unidentified specimen was forwarded to Dr. Mason Hale, who suggested that it might be a species of Dictyonema, perhaps similar to Dictyonema sericeum. A conclusive identification would not be made for another forty years--this past November! A team of scientists sampled the specimen's DNA and found it to be an as-yet unrecognized species, which they named Dictyonema huaorani. Even more fascinating, they were able tentatively ascertain the presence of psychoactive compounds: tryptamines and psilocybin. Psilocybin is notably found in the infamous Psilocybe cubensis (though also in least 200 other species of fungi), but this is one of the first publications indicating psychoactive compounds in lichens!

Although no fresh material is available, the dried specimen hints at how stunning and ethereal this lichen might look. You can also get a good idea by taking a peek at some similar species, of which there are many! Just recently, a molecular study of Dictyonema glabratum revealed the taxon could be split into at least 126 different species. They make for a lovely colour palette!

Lichens are the result of a sort of pact struck between a fungus and something that can photosynthesize, usually an alga. Because the fungus (or mycobiont) cannot produce its own food, it relies on its photobiont partner for sugars. Algae, on the other hand, have a hard time taking up water and staying hydrated. A lichen forms when a compatible alga and fungus team up (see illustrations). The fungus will form a thick protective layer of hyphae called the cortex. Beneath the cortex is a layer of algal cells, photosynthesizing away, suspended above a loose mesh of more hyphae called the medulla. In some lichens, particularly foliose or fruticose ones, a lower protective cortex is formed below the medulla. This is not always the case, though. There are the jelly lichens, which are a jumble of photobiont and mycobiont without any sort of stratification, or lichens with photobiont packed together in cephalodia. Crustose lichens never have a lower cortex: instead, they fuse directly to their substrate. Some lichens are even able to re-assemble themselves in a few months if turned upside-down, moving all of the algae through the medullary layer to face the opposite cortex where they will be exposed to more light.

The lichen complex has been observed primarily among fungi in the Ascomycota, but about 1% of lichens have a basidiomycete as the mycobiont. The photobiont, too, can be a cyanobacterium instead of an algae. This occurs in roughly 10% of all lichens. Dictyonema is particularly bizarre because it is a basidiolichen teamed up with a species of Scytonema, a cyanobacterium!

You can read more about lichens via Lichens of North America or the delightful Ways of Enlichenment.

Dec 5, 2014: Rhytisma punctatum

Another entry from BPotD Work-Learn student Cora den Hartigh today. She writes:

Late autumn is the time locally to observe this common fungus. Richard Droker (aka wanderflechten@Flickr) took these photographs of Rhytisma punctatum a few years ago (image 1 | image 2). This fungus and its relatives are common and widespread wherever maples are found, in Asia, Europe, and North & Central America. Thank you, Richard, for capturing this and for all your stunning microscopic and close-up photography!

An asocmycete, Rhytisma punctatum is known as the speckled tar spot fungus. It is characterized by black freckles on fallen maple leaves. Called "stromata", the little black speckles are actually tough pods of tightly-woven mycelium meant to protect reproductive structures. The mycelium is made up of a web of hyphae, which look like tightly woven threads composed of chitin (the same substance found in insect exoskeletons and butterfly wing scales). Fruiting mushrooms are also woven from hyphae, but are more 'soft' than these little black pods because the hyphae threads are woven less tightly, like a crochet scarf rather than thick work gloves.

These stromata in the images are not mature yet, though! Dormant, they will overwinter on fallen leaves until the spring. Then, as the new maple leaves unfold and in the presence of ample moisture, Rhytisma punctatum will torpedo filamentous ascospores into the air hoping to colonize new growth. Though the force at which they torpedo these ascospores might only carry them about a millimetre, agents such as windy drafts, critters or water might aid them along. Tom Volk at the University of Wisconsin has posted some fabulous pictures of these ascospores.

With its stromata, Rhytisma punctatum resembles freckled pointillism (e.g., some of the work of Seurat). A very similar fungus, Rhytisma acerinum, has larger conglomerated blotches, or "stroma", that exhibit more closely to impressionism (e.g., see Monet or van Gogh).

Usually this fungus is not considered to cause significant damage to the tree. It is often only observable when the black speckles develop in the fall. However, the fungus does cause nitrogen and phosphorus to be retained in the tissue of the leaves rather than withdrawn into vascular tissues in the autumn, which would certainly impact tree vigour.

What I find particularly intriguing about this photo is how some infected, fallen leaves will maintain chlorophyll-green around the fungus even as the rest of the leaf tissues senesce. Known as "green-islands", these colourful spots indicate active photosynthesis. The fungus may be either producing or stimulating localized plant hormone production, e.g., cytokinins, in order to maintain and farm chloroplasts. It can then continue to feed itself and grow, prolonging its active life cycle beyond that of its host. This phenomenon is also known to occur with some leaf-mining insects and their bacterial endosymbionts (see: Kaiser, W et al. 2010. Plant green-island phenotype induced by leaf-miners is mediated by bacterial symbionts. Proc. Biol. Soc. 277(1692):2311-9. doi: 10.1098/rspb.2010.0214 ). Here's a portion of their article abstract:

"...We show that the phytophagous leaf-mining moth Phyllonorycter blancardella (Lepidoptera) relies on bacterial endosymbionts, most likely Wolbachia, to manipulate the physiology of its host plant resulting in the 'green-island' phenotype--photosynthetically active green patches in otherwise senescent leaves--and to increase its fitness. Curing leaf-miners of their symbiotic partner resulted in the absence of green-island formation on leaves, increased compensatory larval feeding and higher insect mortality. Our results suggest that bacteria impact green-island induction through manipulation of cytokinin levels..."

Dec 4, 2014: Daucus carota

Daucus carota

An entry from BPotD Work-Learn student Cora den Hartigh, who writes:

Today, we have a different sort of image from a Canadian photographer living in Munich, Germany. Anne Hoerter takes her subject apart and slowly reconstructs it with photographs, sometimes using up to 40 or 50 images to achieve a single piece that is alive with motion and depth. The graceful movement Anne was able to embody with this stunning artistic representation of Daucus carota, or wild carrot, took three months to produce. Thank you, Anne! You can see more of Anne's work at her website, Áine - Fine Art Photography.

Daucus carota is a familiar umbelliferous species known by many common names, including wild carrot, bishop's lace, and (in North America) Queen Anne's lace. It is a Eurasian and north African native that is widely naturalized in other temperate areas of the world. In North America, one hypothesis is that its initial spread was due to being carried across the continent by settlers in grain sacks. Described by Linnaeus in 1743 in Species Plantarum, Daucus carota has also been recognized widely in poetry and folklore. William Carlos Williams' personifying poem is one example. Williams refers to a purple 'mole' in the white inflorescence. This 'mole' is actually a single anthocyanin-rich flower coloured deep red or purple at the centre of the umbel. Presumably, this single flower helps attract pollinators, perhaps acting as a nectar guide. Another story explains this red flower as a speck of Queen Anne's "blood" dropped from a needle prick while sewing lace.

The little red flower is a particularly useful diagnostic character given that the plant's feathery leaves, floral structure and tall-standing growth habit are similar to a number of poisonous relatives: poison hemlock (Conium maculatum), water hemlock (Cicuta spp.) and fool's parsley (Aethusa cynapium) are counted among these! Unlike many of its toxic family members, Daucus carota tends to grow in dry open habitats and has solid hairy stems. When young, its roots are edible and smell like fresh carrots. With age the roots grow woody and the floral structure curls inward like a vase. I always look for those hairy stems and think of the ditty "Queen Anne has hairy legs"!

In many jurisdictions where the species has naturalized, Daucus carota is considered to be a noxious weed. Doug Larson's oft-cited quote, "a weed is a plant that has mastered every survival skill except for learning how to grow in rows", comes to mind. Brushing up against the leaves can, in some people, cause skin to be more susceptible to UV damage, but this plant can be exceedingly useful. As a companion crop, it boosts tomato production and cools lettuce; as a dyestuff, it imparts creamy tones. Medicinally, the plant dates back to early Greek and Roman writings for digestive disorders, kidney stones, skin tonics, aphrodisiacs, insecticides ... the list goes on. The seeds are also a tasty flavouring for soups and stews not unlike asafoetida; however, they should be consumed with some caution. A relative of Daucus carota, silphium, is thought to have been harvested to extinction for use as a contraceptive and general tonic in ancient Cyrene (Lybia today). So important was silphium that coins were imprinted with the image of the plant. This paper from Economic Botany provides some fascinating archaeological investigation, while Wikipedia gives a good overview. Experimental trials in rats have suggested that extracts from Daucus carota seeds have "...at a lower dose showed anti-implantational activity [of the fertilized ovum into the uterus], whereas higher doses caused fetus resorption. The main effect of the extract appears to be an abortifacient activity." Perhaps not ideal for dinner party soup stock.

Daucus carota has been featured once before on Botany Photo of the Day.

Nov 27, 2014: Stemonitis axifera

An entry from Cora den Hartigh today. Cora writes:

Here is a capture by Anne Elliott (annkelliott@Flickr) of a very small, exquisite organism in a woodpile near Millarville, Alberta (original 1 | original 2). Tiny wonders in the most unexpected of places! Thank you for your sharp eye.

Stemonitis axifera is a cosmopolitan slime mould, pictured here in both its dewy pink youth and rusty-brown spore-producing stage. In the past, being a slime mould meant being associated with mushrooms. Today, slime moulds are classified as multicellular or multinucleate spore-producing amoebas. The University of California, Berkeley has a very useful Introduction to the Slime Molds, where they clearly outline the difference between the multicellular and multinucleate. To illustrate, check out some of these micrographs!

The morphology of slime moulds might seem bewildering, but this delicately coloured glob is simply a bundle of developing, tubular sporangia sprouting from minute, shiny black stalks. When food is scarce, Stemonitis axifera (and other slime moulds) are able to conglomerate their various nuclei and produce sporangia, much like a fungus. Spores from the sporangia are dispersed, sometimes by slugs or other agents, to new habitats where they grow into new amoebae. If they are not in this fruiting stage, slime moulds are very difficult to find, as they creep along the substrate sensing chemicals in the air that might lead them to their favourite foods: bacteria or yeasts on dead and decaying plant matter. In the case of Stemonitis axifera, this is almost always a decaying log.

At the initial stages of conglomeration (the first photo), Stemonitis axifera is a favourite snack of mantle slugs (Philomycus), which snoop about on the exposed surfaces of logs after dusk. The slugs are in a bit of a race against time, though, because once Stemonitis axifera begins to mature, it only takes about 20 hours to complete its life cycle! In 2008, a French study followed a Stemonitis axifera specimen in situ with a series of photographs and recorded the life stages: "eight hours for the induction of sporangia, columella and stalk development, six more hours for rusty-red pigmentation and maturation of sporocarps and a final six hours until spores began to discharge." By the time of Anne's second photograph (when the sporangia are rusty-brown), the slugs lose interest!

Although somewhat unrelated, a fascinating side note: slime moulds are, of course, rare in the fossil record due to their ephemeral nature and lack of vasculature, not to mention the transience of their substrates (dung, moist decaying matter and the like). Nevertheless, some slime moulds have been discovered trapped in Baltic amber! An Archaic Slime Mould in Baltic Amber is a 2006 paper by H. Dörfelt and A.R. Schmidt documenting this discovery from Kalinigrad, complete with some charming photographs of ancient slime moulds!

Nov 6, 2014: Penicillium chrysogenum

Today's entry was written and photographed by Cora den Hartigh. She writes:

Mould isn't often considered beautiful, but I think there is a haunting quality to the gentle blues and soft yellows of this Penicillium chrysogenum. This fungus was cultured on agar medium in the laboratory. Rapid growth hastened a process called guttation, that produced gem-like water droplets suspended on the fuzz of this mould's body. Guttation is common in fungi with some conks oozing blood red or viscous black substances, but it is perhaps most appreciated as a sometimes-contributor to the morning dew on herbaceous plants. If you aren't yet convinced of the beauty of this mould, perhaps the elegance of Penicillium's conidia strung in beads from draping conidiophores under a microscope will prove convincing. If flowers had skeletons, maybe they would look like this!

Aesthetics aside, Penicillium is the famous fungal genus that contributed to the discovery of penicillin, the antibiotic whose discovery opened up a new field of medical treatments. As fungal hyphae stretch into substrates in search of food, they release enzymes to break nutrient sources down for ease of absorption (somewhat akin to having an external stomach). The catch is, they must then protect their processed foods from competitors! Penicillin is just that, an antibacterial that Penicillium uses to protect its plate at dinnertime. It is worth mentioning that Penicillium chrysogenum was discovered on a cantaloupe in Illinois and is not the same as Alexander Fleming's Penicillium notatum, which produces significantly less penicillin. However, it was Penicillium chrysogenum that contributed to the mass-production of penicillin. Resistance to antibiotics is becoming an increasing concern globally; it is a bolstering thought that there remains a vast diversity of fungi yet undiscovered that may have similar potential.

Daniel adds: Tom Volk's always excellent Fungi site has a detailed article on Penicillium chrysogenum, with additional details about the discovery and history of penicillin.

Oct 30, 2014: Rhizomnium glabrescens

Rhizomnium glabrescens

Cora den Hartigh returns with her second written entry. Cora scribes:

Poking through the Botany Photo of the Day Flickr Pool, I was thrilled to find photographers such as Don White (Don White@Flickr | original image) who also share my enchantment with the spindly and mysterious world of sporophytes. Thank you for appreciating little wonders!

This intriguing picture captures Rhizomnium glabrescens, commonly known as fan moss or large leafy moss. This is a common species along western North America's coast from Alaska to California. It also occurs sparingly eastward into Montana. Prime habitat is on logs in coniferous woods on logs or areas with rich humus-y soil. This little bryophyte will cushion many a woodsy step! It is named for its smooth stems (Rhizomnium = "rhizoid-bearing moss", glabrescens = "smooth"). The leaf blades or lamellae of Rhizomnium glabrescens are unistratose, or only a single cell layer thick. This lends a ghostly delicate quality to the lush mats formed by these mosses. Sunshine often renders them nearly transparent, like this! This moss is particularly dazzling in the dappled sunlight where it glimmers, particularly when it has collected water droplets.

Sadly, mosses haven't garnered great interest from humans as useful plants. They are small and tend to have few economic uses. I was very excited, however, to find that Rhizomnium glabrescens was utilized as a poultice to reduce swelling by at least one First Nations group, the Makah.

A slightly curved operculum--the little cap at the tip of the sporangia--is diagnostic of this species; once mature and dry, the operculum will dehisce or pop off to expose rows of peristome teeth (yes, moss have teeth!!) which rely on the ambient humidity to move, flicking spores inside the sporangia outwards. UBC's Biology 321 (Introduction to Bryophytes web site is the source of many of today's links. The site has other excellent photographs of this species on this page: Rhizomnium glabrescens. This moss has a cute rosy seta, or stem-like structure, which stretches tall to aid dispersal in the springtime, an excellent time to catch mosses at work! But, since it is autumn and spring feels a long way off, you can experience more of Rhizomnium glabrescens on E-Flora BC and the Central Coast Biodiversity website.

Oct 22, 2014: Chondracanthus exasperatus

Chondracanthus exasperatus

Another new writer today: Cora den Hartigh is a Botany Photo of the Day work-learn student. Like Tamara, Cora is joining us for at least the next six months. For her first entry, Cora writes:

Instead of land plants, here is something associated with the ocean courtesy of mycologie@Flickr (original photo). Thank you for the refreshing splash of maroon!

This resplendent red macroalgae is known as Chondracanthus exasperatus, or Turkish towel, and it is a rather common species along the Pacific coast of North America from Alaska to Mexico. Its rich colour is due to phycoerythrin, an accessory pigment that works in tandem with phycocyanin to facilitate light harvesting at depth. When wet, Chondracanthus exasperatus may take on iridescent tinges not unlike the stunning Mazzaella splendens (previously known as Iridaea splendens,which I personally think was a very lovely name). The iridescence is akin to the rainbows caused by oil or gasoline in water - in fact, layers of oil or cuticle in these seaweeds are indeed what refract light differently, reflecting various colours. It is particularly difficult to capture this refraction and reflection in a single photograph. It is easier to see in-person or with a video like this one, from a diver who chose to record the underwater shimmer! If you are interested in learning about a few other types of seaweed along the western North American coast, see An Introduction to the Seaweeds of British Columbia, an excellent overview written by UBC graduate Colin Bates.

Back to Chondracanthus exasperatus! Preferring lower intertidal zones, this raspy algae attaches to rocks with a disc-shaped holdfast, sort of like an anchor. Its long leaf-like blades can grow over a meter long and often wash up after storms, to the delight of the discerning beachcomber! Papillate blades of Chondracanthus exasperatus have excellent exfoliant properties and can be used in the bath or shower in lieu of a loofah (hence the common name). These bumpy papillae are quite variable; this photograph demonstrates some marvellous undulation, as opposed to the coarser textures that might indicate a vegetative state. Both antibacterial and high in carrageenan (also a food thickener), these natural scrubbies are often sold as beauty aids. I myself have attempted to gift precious specimens of this seaweed in the past, but the recipient was not impressed: "Ick! It smells like saltwater! You think I'm going to use THAT in the shower?!" Despite my assurances that the algae's cells were highly saline, would burst when faced with fresh bathwater, would disintegrate after about three or four days, and would never clog plumbing, my words were not convincing. Perhaps you will appreciate Turkish towel's ocean charms!

Can't get enough seaweed? Bamfield Marine Sciences Centre's OceanLink has a helpful page on algae of the red persuasion, and their overview of seaweeds is a valuable resource too!


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