Yesterday evening was only the fourth time since the beginning of April when I've had the opportunity to photograph in the garden — a somewhat worrying statistic for me. I've been fortunate enough to be able to travel this summer, but not being out in the garden often enough to observe the seasonal progression has been a bit disappointing.

Stemless carline thistle or dwarf carline thistle is native to the mountainous areas of central and southern Europe. The epithet acaulis means “without a stem”, but as you can clearly see in this photograph, this plant certainly has one. That suggests that this is either subspecies simplex (a stemmed subspecies of the plant) or a garden hybrid with Carlina acaulis subsp. simplex as part of the genetic mix.

In addition to the usual edibility (a globe artichoke substitute!) and medicinal use information often detailed in the Plants for a Future database, the entry on Carlina acaulis lists another use: weather forecasting. PFAF cites a reference that suggests the dried flowers of Carlina acaulis can be used to measure humidity, whereas the mature flowers of a plant will close prior to a rainfall. I'll have to keep a closer eye on them to verify the latter...

More information can be found on Wikipedia, including a photograph of a plant with a sessile (acauline) flower. A botanical illustration of Carlina acaulis is available via Thomé's Flora von Deutschland.

Thanks to David Tarrant are once again in order for today's photograph from Mexico. Appreciated as always, David.

Despite a specific epithet (roseus) that translates to “pink”, the common name often used in the USA for this species is white rocklettuce. Pink dandelion is also sometimes used, as is white dandelion. Curiously, it seems the plants growing in the northern part of its range (south-central USA) tend to have little pink colouration (e.g., these photographs from the Lady Bird Johnson Wildflower Center), while those growing in the southern part of its range (central Mexico) are quite pink (e.g., today's photograph and this other photograph from Mexico).

This is a follow-up photograph to last year's BPotD on Magnolia delavayi (or Delavay's magnolia). Peter Wharton described the plant in a comment accompanying that entry, so I'll direct you there if you'd like to read more.

Last week, the garden received a paper-copy of the Red List of Magnoliaceae, published jointly by Fauna & Flora International and Botanic Gardens Conservation International. From a global list of 245 magnolia species, over half are identified as being in danger of extinction in the wild (including Magnolia delavayi). The list makes for very sobering reading, particularly as it is difficult to imagine a scenario whereby changes are made to prevent the loss of many of these species.

Botany Photo of the Day will have brief written entries on weekends, holidays and my vacations from April through September. – Daniel

Thank you to MagnetFL@Flickr for sharing today's photograph with us (original | BPotD Flickr Group Pool). Much appreciated!

Spotted beebalm or spotted horsemint is native to the eastern United States. The USDA PLANTS database reports it being present in California, but the Jepson Flora Project states that the record of the plant occurring in California was based on an erroneous report.

The Lady Bird Johnson Wildflower Center has an excellent factsheet (though it also cites this species as growing in California). The Plants for a Future database details the traditional medicinal uses.

Another photograph from San Miguel de Allende in Mexico today, courtesy of David Tarrant. Thanks once again, DT.

This is one of those plants that has a bit of a story here at UBC Botanical Garden. When David was hosting the Canadian Gardener television show (though continuing well after), people would send in plants to David to be identified. According to David, every year someone would send in this strange, spiny plant, and every year, he and Judy Newton (the garden's former education coordinator) would be puzzled by it until they asked Gerald Straley. Gerald would of course identify it, and then David and Judy would recall they had encountered it last year... and the year before that... and the year before that. I was witness to one of these occurrences in the early 2000s, though it was Douglas Justice identifying the plant after much puzzlement on the part of David, Judy and myself. David reports that his new hometown is surrounded by it, so that he'll now never forget.

Buffalobur (or buffalobur nightshade or buffaloberry) is native from central Mexico north to the midwest USA, but the introduction of intensive agriculture has since helped it spread throughout much of North America. It has been introduced to other continents, where it is considered a weed (if not an invasive plant) in parts of Russia and Australia. The Washington State Noxious Weed Control Board has assembled a handy factsheet about Solanum rostratum.

More photographs of buffalobur can be seen via MissouriPlants.com.

Thank you to Nuytsia@Tas on Flickr of the UK for sharing today's photograph with us (original | BPotD Flickr Group Pool). Much appreciated!

Nuytsia@Tas also has an excellent written accompaniment to this photograph of field cow-wheat (an annual hemiparasite), so I'll start off by quoting:

“A schedule 8 rarity of the British Isles, this plant is now known from only two or three sites. ”

“The level of parasitism in this genus is high with most species failing to get past the cotyledonary stage if grown without a host. The seeds are amongst the largest in the Orobanchaceae, so much so that the capsule only holds a pair of seeds. Peculiarly the capsule splits to release the seeds wet, which essentially just drop out.”

“The seeds themselves have a fatty elaiosome at one end. It is this elaiosome that enables dispersal of the seeds. Ants collect the seeds eat the elaiosome and then discard the seeds. The seeds have a rather complex dormancy and germinate during a following winter/spring period. ”

One of the reasons for its rarity in the British Isles is that it was purposefully extirpated (PDF). Once a common weed of fields, people were employed to hand-pull it. This animosity was directed towards the plant because the presence of its seeds in grain to be milled would contaminate and sour the flour. The Species Action Plan (PDF) for cow-wheat cites some local threats to existing populations in the UK, including erosion into a lake.

The species is distributed throughout Eurasia; the Species Action Plan link above points out that it is considered rare throughout the western European part of its range, but no mention is made of its relative rarity in the east.

Another thank you to Anne from Alberta (aka annkelliott@Flickr) for contributing a photograph to BPotD (original via BPotD Flickr Group Pool). Appreciated as always, Anne!

Bebb's sedge is distributed throughout wetland areas of temperate and subarctic North America. Like most members of the Cyperaceae, or sedge family, it has a wind-pollination strategy (i.e., it is anemophilous), with (relatively) “large anthers, long filaments and prominent stigmas” (source: Wendy Zomlefer's Guide to Flowering Plant Families). Without the need to attract insects, the flowers are also apetalous and asepalous (lacking petals or sepals). An alternative way of describing this phenomenon is to say that the perianth is absent.

Most identification keys for Carex species require the plant to have mature fruit, one of the many reasons that botanical field surveys of areas without the luxury of being able to continue fieldwork into the late summer or autumn simply state “Carex spp.” (meaning multiple unidentified species of Carex) in the final list of plant species collected. Plants collected earlier in the year with only vegetative and flowering characters can be extremely difficult to identify to species. The plant in today's photograph likely has mature fruit (or close to it), though the achenes (dry, one-seeded fruits) are hidden within the sac-like perigynia.

Much to the frustration of students learning about the Cyperaceae, though, Carex identification is often difficult even when a specimen has mature fruit. Writers of identification keys sometimes like to throw in a couplet or two about the flowering characteristics midway into the key, which, of course, will not be present in the specimen in front of you (because you collected the plant when it had mature fruit like you were supposed to!). You then learn that a) you actually need to have specimens from the same group of plants in different reproductive stages or b) you need to become a good guesser and expert at the trial and error method of identification. Option b, I think, is quite a popular option.

I couldn't resist highlighting a photograph (original via BPotD Flickr Group Pool) from the recent additions to Eric in SF@Flickr's From the Earth photo set – if you're a fan of colour and patterns, the photographs are a must-see. Thanks once again, Eric!

As Eric points out, the Wikipedia entry on bitter melon is a good starting point to learn more about this widely-grown vegetable, as it describes the plant, highlights the culinary and medicinal uses and provides common names in two dozen languages. From the common names, it is easily inferred that it is cultivated pantropically (though African common names are absent). Flora Zambesiaca, though not providing any African common names, provides the best scientific description of the plant, though: Momordica charantia.

An image search for Momordica charantia reveals a diversity of form for this vegetable (and this stamp with an illustration of the ripe fruit from the Cucurbit Network). I think the hybrid in today's photograph is one of the Indian cultivars. As always, though, I'm open to being corrected.

If you're going to search for more information on bitter melon, you'll find the search engine results cluttered with various medicinal claims, particularly in regard to diabetes. Do note that in Bitter melon (Momordica charantia): A review of efficacy and safety, Basch et al. conclude “Bitter melon may have hypoglycemic effects, but data are not sufficient to recommend its use in the absence of careful supervision and monitoring” (American Journal of Health-System Pharmacy. 60(4):356-359).

Entomology / art resource link: Trichopterae, “an unusual artistic collaboration between the French artist Hubert Duprat and a group of caddis fly larvae” in Cabinet Magazine.

Botany Photo of the Day will have brief written entries on weekends, holidays and my vacations from April through September. – Daniel

Thanks again to Krystyna Szulecka, for sharing today's photograph with us (original in this thread on the UBC BG Forums). See more of Krystyna's images by searching for “Krystyna” on the FLPA web site.

Lava cactus is endemic to the volcanically-formed Galápagos Islands, where it is a colonizer species of lava fields (hence the common name). Due to its narrow geographic distribution, it is listed as a vulnerable species on the IUCN Red List.

More photographs can be seen via Thomas Schoepke or CalPhotos.

Botany Photo of the Day will have brief written entries on weekends, holidays and my vacations from April through September. – Daniel

Thank you to shotaku@Flickr from Missouri, USA for contributing today's photograph (original via BPotD Flickr Group Pool). Much appreciated!

One will often find this cultivar under the (incorrect) names Clematis 'Lanuginosa Candida' or Clematis lanuginosa 'Candida'. The Royal Horticultural Society points out, however, that Clematis 'Candida' should be used. The genes of Clematis lanuginosa are indeed found within this cultivar, but that species is one of two parents of this hybrid (the other being Clematis patens).

Botany Photo of the Day will have brief written entries on weekends, holidays and my vacations from April through September. – Daniel

kai kane@Flickr, aka Peter F. from Gloucestershire, England is the photographer behind today's BPotD (original via BPotD Flickr Group Pool). Thanks, Peter!

As the cultivar name implies, these diminutive lilies grow to a height of only 30-45cm (12-18in). Paghat writes about her experiences with Lilium 'Orange Pixie' (and includes some history of the plant, as well).

Botany Photo of the Day will have brief written entries on weekends, holidays and my vacations from April through September. – Daniel

Another couple photographs from Mexico today, courtesy of David Tarrant – thanks again, David!

Parrot-flower mistletoe is a member of the plant family Loranthaceae, the largest of the “mistletoe families”. Psittacanthus relies on birds twice in its life-cycle: once for pollination and again for dispersal of seeds (the birds eat the fruit and defecate the seeds on branches).

Though this particular plant is not parasitizing a conifer, the best information online on “Psittacanthus in Mexico” that I can find is a chapter by the same name in Mistletoes of North American Conifers (PDF), a cooperative technical report by scientists in USA, Mexico and Canada.

Botany Photo of the Day will have brief written entries on weekends, holidays and my vacations from April through September. – Daniel

In terms of global cereal crop production, wheat is second only to maize (corn) (though it sometimes yields the number two spot to rice, depending on the year). China, India and the USA are the world's top-three producers – not so coincidentally, these are also the three countries with the largest populations. Read “The Story of Wheat” from the December, 2005 edition of The Economist for details about the history and future of this exceedingly important crop.

Botany Photo of the Day will have brief written entries on weekends, holidays and my vacations from April through September. – Daniel

Georgie Sharp@Flickr is the photographer of today's image (original via Flickr BPotD Group Pool). Thank you, Georgie!

Collectively, eremophilas are also known as emu bushes, hinting at their distribution in the dry lands of Australia (note that this photograph was taken at the Australian Arid Lands Botanic Garden). Australian Plants Online has an extensive article about the genus Eremophila, including photographs of flowers from a number of species.

Botany Photo of the Day will have brief written entries on weekends, holidays and my vacations from April through September. – Daniel

Another thank you to Eric in SF@Flickr for sharing a photograph with us (original | BPotD Flickr Group Pool). Much appreciated!

Lace hedgehog cactus is a plant of the southern USA and northeastern Mexico. It forms part of a species group, listed by the Flora of North America as including <“E. reichenbachii, E. chisosensis, E. rigidissimus, E. pseudopectinatus, and an indefinite number of Mexican species”. The Lady Bird Johnson Wildflower Center has a small factsheet with a series of images.