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

Jul 30, 2015: Oenothera elata subsp. hookeri

Oenothera elata subsp. hookeri

I have always thought of the evening primroses as particularly romantic plants. Many of the Oenothera have richly-scented blooms that open in twilight. Their light-coloured petals make them gleam in the dusk light like rising moons. John Rusk's (aka John Rusk@Flickr) photo of Oenothera elata subsp. hookeri captures the romance of Hooker's evening primrose perfectly. Thanks John!

Some sources list four subspecies of Oenothera elata. Oenothera elata subspecies hirsutissima occurs in the western United States into the Mexican states of Baja California and Durango, while subspecies elata is found in central Mexico south into Central America. Subspecies hookeri occurs in moist coastal sites in California. Subspecies texensis is known from a single specimen collected in Texas (as of 1987), though not all public databases incorporate this last subspecies.

Oenothera elata is tall for an evening primrose, reaching heights of well over one meter. It sends up near-erect flowering stems, which bear flowers that open from the bottom up. The bisexual flowers are about 8 cm across. They are yellow and darken to orange with age. Each flower has four heart-shaped petals and four smaller sepals that may be fused in pairs. One unusual feature of evening primrose flowers are their X-shaped stigmas that extend out beyond the petals and stamens. Today's photo shows this property--the stamens look particularly unusual when extending beyond the furled petals of the spent flowers.

The flowers open in the evenings, timed for Oenothera elata's main pollinators: hawk moths (often Hyles lineata). One of the most amazing aspects of evening primroses is that their flowers open very quickly, some in under a minute. The Yosemite National Park website has a great video of an Oenothera elata subsp. hirsutissima flower opening. In the paper, Flower opening and closure: a review, van Doorn and van Meeteren explain that opening Oenothera flowers release their petals suddenly. This occurs because the cells at the margins of the sepals are connected in a zipper-like structure. As the petals grow, they break through the zipper and quickly spill out. Depending on the species of Oenothera, flower opening might be triggered by light levels or relative humidity. Other species of evening primrose appear to have an endogenous (internal) rhythm that triggers opening.

Jul 29, 2015: Kopsiopsis strobilacea

Kopsiopsis strobilacea

Today's photo features the yellow morph of Kopsiopsis strobilacea. This Pacific Northwest species is a member of the Orobanchaceae, or broomrape family. Thank you to Alan Tracey, who took this photograph near Selma, Oregon.

Botany Photo of the Day has recently covered another parasite, the mycoheterotrophic Allotropa virgata. Like Allotropa virgata, the non-photosynthetic Kopsiopsis strobilacea relies on a host for its survival. Allotropa virgata, however, obtains its food from a fungus, whereas today's species taps directly into flowering plants for its meal. Kopsiopsis strobilacea is termed a holoparasite (it cannot complete its life cycle without a host). It is also known as a root parasite, as it connects to the roots of its host. Kopsiopsis strobilacea parasitizes madrone trees (Arctostaphylos spp.) and manzanita shrubs (Arbutus spp.).

The common name for Kopsiopsis strobilacea is California ground-cone. Today's photo of the yellow morph of the species provides a hint of its resemblance to a cone from a coniferous tree. The more common form of Kopsiopsis strobilacea is dark purple to brown, and looks even more like a conifer seed cone. A photo of a more typical California groundcone was featured on BPotD in 2008 (posted under a previously-used synonym for the species, Boschniakia strobilacea), and it gives a good indication of how well this species might blend into the Pacific Northwest forest floor. No matter how cone-like Kopsiopsis strobilacea looks, its flowers reveal that it is a member of the Angiosperms (the flowering plants). The four-lobed flowers stick out from the scale-like bracts in the spring.

The 2008 entry shows another key aspect of this species: its root-like haustorium. Unlike most flowering plants, Kopsiopsis strobilacea lacks roots. Instead, it has a haustorium, whose purpose it is to penetrate the roots of its host and to withdraw water and nutrients. In the book, Parasitic Orobanchaceae, Joel, Gressel, and Musselman explain that holoparasitic Orobanchaceae are able to germinate independently of a host. As seedlings mature, the haustorium develops at the tip of the radicle (the embryonic root). Next, the seedling develops an attachment organ - in most Orobanchaceae this consists of specialized root hairs (haustorial hairs) arranged around the penetration site. The haustorial hairs are covered by a glue-like secretion that cements the hairs to the host. During this time, intrusive cells form. Once the the attachment organ has completed its task, these cells penetrate the host root. Although some parasites penetrate their host by dissolving the host's cell walls, Joel et. al. assert that this is not the case in Orobanchaceae. Kopsiopsis strobilacea enters its host by mechanically pushing its way between the host's cells, aided by enzymes that degrade the host's cell wall.

Jul 28, 2015: Cyperus trachysanthos

Cyperus trachysanthos

Thank you to frequent contributor David Eickhoff (aka D.Eickhoff@Flickr) for this photo of Cyperus trachysanthos. The green and brown pattern playing vertically along overlapping triangular spikelets makes this the most beautiful sedge inflorescence I have yet seen.

Cyperus trachysanthos is a perennial, rhizomatous species of sedge. The densely-growing culms (the above-ground stems of a grass or sedge) are triangular in shape and can reach a height of 45 cm. The leaves are slender and coated with a sticky wax, giving Cyperus trachysanthos its common name of sticky flatsedge. The inflorescence is quite striking. It is composed of a few heads, each with up to 30 spikelets. The 20 cm spikelets have up to 20 flowers that are covered by yellow-brown glumes (outer sterile husks).

David writes that this photo was taken along the Lower Kamananui Stream in the Waimea Valley of O'ahu. He explains that this specimen was "probably an escapee from the upper man-made ponds where it is planted." Cyperus trachysanthos is endemic to the Hawaiian Islands. It is an endangered species. A US Fish and Wildlife Service 5 Year Review (PDF) found that there were only two populations of Cyperus trachysanthos with over 50 mature individuals. Efforts are being made to restore sticky flatsedge to parts of its range where it is no longer found. New populations are also being established on suitable sites. If some of these new populations are spreading downstream, this is good news indeed.

Cyperus trachysanthos is gaining popularity among Hawaiian gardeners. Hawaiian nurseries that stock this species recommend gardeners plant it in moist areas or around water features. Sticky flatsedge can be used for mass plantings. It also makes a great accent, particularly if planted among ground-covers or rock features. The inflorescence purportedly makes a fabulous addition to floral arrangements.

Jul 27, 2015: Helichrysum splendidum

In early July, I was wandering through the University of British Columbia Botanical Garden looking for bees. I was joined by Bailey Wilson, a summer intern who is cataloguing the native pollinators that use the Garden. This Helichrysum splendidum bush was the perfect place to start looking at the different ways that bees use some of the Garden's collections.

In our search for pollinators, Bailey and I gravitated to plants with the most grandiose display of flowers, as we thought these would receive the most interest from bees and other pollinators. We were perplexed when we saw how popular Helichrysum splendidum was with the bees. At the time, this bush had only a smattering of little yellow flower heads. Most surprisingly, the woolly leaves seemed to hold more appeal than the flowers. Bailey and I sat back and watched the bees flitting around for a while. Some bees landed on the flowers, while one specific type of bee would land on the leaves and use its front legs to rake little balls of wool towards its abdomen. I had never noticed such behaviour, and became quite smitten by this little, adorable bee.

It turns out that this quirky bee is a European wool carder bee (Anthidium manicatum). They are well known for scraping the hairs off a common garden plant, lamb's ears (Stachys byzantina). They use plant hairs to line their nests. I imagine the thick, woolly white hairs of Helichrysum splendidum make fine nest material indeed. Despite my infatuation with the bee that I photographed, it seems these are a bit of a nuisance. Originally a European species, these pollen generalists have spread to North Africa, Asia, and North America. Their range is continually expanding. The males aggressively defend their woolly plants as well as their females. I saw only females of the species, whose task it is to collect the hairs.

Helichrysum splendidum grows quickly and forms an attractive dense, silvery-grey mound. Compact flower heads bloom at the tips of branches. The inflorescences of Helichrysum splendidum are corymbose panicles of calathids, initially containing tight yellow buds. These papery buds open over a period of several weeks, revealing clusters of darker yellow flowers within. Like most Helichrysum species, the flowers are "everlasting"--they maintain their form and colour when dried. Many of the common names for this species refer to this quality. One example is the Afrikaans name sewejaartjie, derived from the words for seven (sewe) and years (jaar), representing the amount of time that it is believed the flowers last when kept in the house.

Jul 24, 2015: Nymphoides peltata

A small constructed pond sits on the low side of UBC Botanical Garden's EH Lohbrunner Alpine Garden. This pond was absolutely "hopping" (bad pun intended) with activity on a hot day during an unusually dry July. Many Pacific tree frogs (Hyla regilla (PDF) were sunning themselves on the leaves of Nymphoides peltata. In the water were hundreds of tadpoles nearly ready to join them.

The frogs were a treat to see, but other signs of wildlife around the pond reminded me of the ecological importance of water. As I approached the pond's edge, I initiated a flurry of activity as water striders, birds and bees hurried to move away. For my part, I had to watch out for the coyote scat that lay along the mossy bank. This small pond is clearly an important source of refreshment in a region that is experiencing "drought level 4" (a level of drought at which the water supply is insufficient to meet ecosystem and socioeconomic needs).

This species, also known as yellow floating heart, is often planted by North American water gardeners. It is easy to grow in shallow ponds that have little moving water (the second photograph by Daniel shows it growing in a pond in Vancouver, Canada's Queen Elizabeth Park). The heart-shaped leaves display slightly different hues of green, and I find the pattern that they create as they sit just at the water's surface very calming. And of course, there are the inflorescences. These are bright yellow and held about 3 cm above the water by stalks that each support two to five flowers. The five petals have a delicate fringe along their margins. Each flower blooms for one day. Van der Velde and Van der Heijden (1981) explain that the development of flowers occurs in a sequence, so that each Nymphoides peltata stand blooms over a long period of time (June to October).

Nymphoides peltata produces capsules with numerous floating seeds that can spread downstream. It can also reproduce vegetatively from stems, roots, and even leaves. Unfortunately, in many parts of North America, cultivated Nymphoides peltata have escaped into the wild. It is considered an invasive species in many states of the USA as well as in the Canadian provinces of Ontario and Quebec.

In its native range of temperate Europe, temperate Asia, and a bit of subtropical Asia, Nymphoides peltata plays an important role in its ecosystem. Its long flowering period and ability to form large stands makes it crucial to many pollinator species (see 1981 article linked above). Despite its weediness in North America, Nymphoides peltata is considered a vulnerable species in Japan, where it once commonly grew wild. Takagawa et. al. 2005 found that only one Japanese population, in Lake Kasumigaura, retains the potential for sexual reproduction.

Jul 23, 2015: Furcraea parmentieri

Thank you to Annette Arundel (aka RosinaBloom@Dave's Garden) for agreeing to share this photo of a towering Furcraea parmentieri inflorescence. Gareth Winter provides the other great photo featured today, showing a Furcraea parmentieri rosette. Thank you Annette and Gareth!

I am writing about Furcraea parmentieri on the request of one of our readers. A synonym for this species is Furcraea bedinghausii, named after Hermann Joseph Bedinghaus. Says our reader, "(Bedinghaus) produced one of the earliest commercially useful cultivars of gladiolus, Gladiolus x gandavensis Van Houtte, and is considered to be a founding member of the gladiolus fraternity." This reader has been having a difficult time finding more information about Bedinghaus, and is hoping one of you can provide her with more information. Please comment if you are a Bedinghaus scholar!

Furcraea parmentieri is endemic to Mexico, growing only in the Trans-Mexican Volcanic Belt. It is the most prominent species in an ecosystem type that Velázquez and Cleef (1993) (PDF) call the mega-rosette community. Mega-rosette indeed. The young plants of Furcraea parmentieri form a rosette of stiff, blue-grey leaves. As these plants mature, a tall trunk forms, felted with the remains of old leaves. The trunk may reach a height of 3.5 meters, giving Furcraea parmentieri a palm-like appearance.

Somewhere between the age of 15-50 years, Furcraea parmentieri plants send up an impressive, 3 meter-tall inflorescence bearing panicles of white to cream-coloured flowers. Despite an abundance of flowers, Furcraea parmentieri seldom forms fruits. The article, The Community of Furcraea parmentieri: a threatened specie [sic], Central Mexico (2013), notes that wild populations of Furcraea parmentieri are genetically very similar, indicating that this species primarily reproduces clonally rather than through seed. It does this by forming hundreds to thousands of bulbils--plantlets that form in the axils of the bracteoles (the small leaf directly below the flower) of the mother plant. Since the bulbils form only on the inflorescence, Furcraea parmentieri's method of vegetative reproduction is, ironically, intimately linked to flowering. Following the senescence of the flowers, the mother plant will die (as do all monocarpic species). If it is lucky, at least some of its bulbils will take root and begin the cycle anew.

Although Fulcraea parmentieri has a limited native range, it is hardy to temperatures of -5°C provided it is planted in a dry, free-draining soil. Some private and botanic gardens in Europe, North America, and Australasia cultivate Fulcraea parmentieri as an ornamental species. One of today's photographers, Gareth, comments that the Dunedin Botanic Garden has a particularly nice display of this species. Gareth also notes that individual Fulcraea parmentieri plants tend to flower during the same year (a phenomenon known as masting). This creates a spectacular show, but leaves a sad absence in the garden once all the mature plants have died.

Jul 22, 2015: Synthyris cordata

Today we feature two lovely photos taken by Alan Tracey. These photos show the herbaceous perennial Synthyris cordata growing on a rocky bank in Oregon. Thanks Alan!

Synthyris cordata is sometimes considered synonymous with Synthyris reniformis, or sometimes asserted as being Synthyris reniformis var. cordata. Synthyris cordata is distinguished from Synthyris reniformis by narrower leaves and unicellular hairs on the inner corolla tube. John Schenk, in the article, Sorting out Oregon's Synthyris (PDF), points out that research indicates that today's species represents a distinct lineage that originated from Synthyris reniformis. Adding to the complicated nomenclature of this species is the fact that Synthyris has recently been moved from Scrophulariaceae to Plantaginaceae.

Today's species is endemic to southwestern Oregon and northwestern California. It is commonly known as serpentine snow queen, as it grows in decomposing serpentine soils. Snow queen is a reference to it being one of the first flowers to bloom in spring. Although the flowers are very small, they possess a humble beauty. Each inflorescence gently curves upwards, holding 5-10 light blue, bell-shaped flowers. Two darker blue stamens peek out just beyond the edge of the corolla. When these perfect flowers become pollinated, they form capsules with two valves that hinge open. These valves are typical of the genus, providing its name (syn = together, and thyris = little door).

Synthyris cordata has clumps of basal leaves that are somewhat variable in shape. They are described as ovate to widely ovate, with a base lobed to cordate and a tip acute to obtuse. The epithet cordata in this species' name refers to heart-shaped leaves, while the epithet reniformis in Synthyris reniformis refers to leaves that are kidney-shaped. I can't quite come up with it, but I think there must be an easy mnemonic involving hearts and kidneys that could help us remember how to tell the two species apart. Anyone want to give it a try?

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