The photographs of Platanus wrightii a couple days ago inspired Dr. Quentin Cronk to submit his photographs of Platanus occidentalis, or American sycamore (or American planetree), from Eno River State Park in North Carolina. Coincidentally, he took these photographs two days before I took the ones in the Chiricahuas.

Dr. Michael Dirr has this advice to give on the landscape value of this tree in his “Manual of Woody Landscape Plants” : “If native to an area do not remove the tree(s); however, do not plant it...”. Dr. Dirr cites diseases and pests such as anthracnose and borers along with the messiness of its fallen leaves and fruits as some of its undesirable characteristics. He considers the potential diseases and insects so bad that he concludes the list with “ad infinitum”.

The Flora of North America entry for Platanus occidentalis notes: “Of the angiospermous trees of North America, Platanus occidentalis is one of the tallest (to 50+m) and reaches the greatest trunk diameter (to 4+m)”. Too bad this species is not suited for cultivated landscapes – its size and intriguing bark (amply demonstrated here by Quentin) would make it very appealing as a specimen tree in a large park.

Art resource link: I've linked to this site previously, but the American Society of Botanical Artists has a listing of upcoming art exhibitions in Brooklyn, Pittsburgh, New York, Seattle, Tucson and Melbourne. If you live in (or plan to be visiting) any of these cities, you might like to take the time to visit one of these exhibitions. I'll be visiting the one in Seattle, myself.

A thank you to Monika (half of monika&manfred@Flickr) for submitting today's photographs taken in Vienna, Austria (original image 1 and original image 2). It's worth the time to browse Monika's photographs, particularly since she has photographs from her travels around the world.

The question to ask with cucurbits is, “What aren't they used for?” If you read The Wild and Wonderful World of Gourds from Wayne Armstrong, you'll learn members of this family were or are used for: food, medicine, ornament, a sweetener, currency, an art medium, containers and eating utensils, pipes, musical instruments and clothing – not a bad list!

I believe most, if not all, of the cucurbits in today's photographs have wild origins in Mexico and South America, though if the pale one is actually a melon (Cucumis melo) instead of a squash, it would have its origin in Africa or southwest Asia. Members of the family are found throughout the tropical, subtropical and warm temperate areas of the world.

As an aside, you'll recall how I mentioned Arbutus menziesii is oft a subject of photographers. For proof, see ngawangchodron's Arbutus menziesii – fifty photographs so far!

I thought I'd follow up yesterday's Arbutus menziesii with another tree species I am anxious to spend more time photographing. These photographs were taken in late March.

Platanus wrightii, or Arizona sycamore, is one of ten species in the genus Platanus; in turn, Platanus is the only genus in the family Platanaceae. The genus Platanus has an odd biogeographical distribution: 1 species found in Vietnam and Laos, another in southeast Europe and southwest Asia, and the remainder in eastern North America, southwest USA and Mexico. The centre of diversity for the species is certainly Mexico, where six of the ten species occur. It reminds me of the distribution of Styracaceae, though more restricted in scope and entirely absent in South America – I'll follow-up with a post about the Styracaceae in a later BPotD.

You might notice in the landscape photograph that the trees are found at the base of the rocky hillsides. More specifically, they are typically found along watercourses which would perhaps be better illustrated with an aerial photograph (I didn't have a spare airplane, though).

The second photograph is an attempt to demonstrate what I consider the ghostly nature of these trees. I like to imagine I'll be able to spend a few weeks sometime making more attempts.

By the way, if you're interested in a close-up of the bark, you can visit this “stumper” I posted on the UBC discussion forums (What is a stumper?).

Two photographs of arbutus (or Pacific madrone) from my 4-day mini-holiday on Galiano Island. It's easy to imagine why some local photographers occasionally have exhibits dedicated to this, Canada's only evergreen deciduous broad-leaved tree (the word “deciduous” was struck out and then later restored - see comments). Myself, I took about a hundred photographs, though most were abstracts and won't find their way onto BPotD. You can see why I'm eagerly anticipating the development of UBC Botanical Garden's Garry Oak Woodland and Meadow, since it will contain two groves of dozens of mature arbutus trees when planted out.

For a bit of information about this species, visit last year's entry on Arbutus menziesii.

A second thank you in the span of three days to van+s@Flickr for contributing a photo (original image | BPotD Flickr Group Pool). This plant was cultivated indoors at Brooklyn Botanic Garden. Thanks again, van+s!

Pretty as it is, this particular lachenalia has the potential to escape from cultivation and become weedy, as has occurred in Western Australia. The fact that it is common and widespread in its native Cape region of South Africa serves as a hint that it is adaptable, and thus likely to pose problems in non-native environments with conditions similar to the Cape.

The epithet “mutabilis” means “changeable”, in this case referring to the inflorescence – the immature stalk and flowers start blue and turn yellowish-green or pinkish as they age. For photographs of the entire inflorescence with the range of colours, see this page from the International Bulb Society and the Lachenalia page from the Pacific Bulb Society's Wiki.

Photography resource link: Nature's Best Photography Magazine's International Awards – scroll down in the middle frame of the page for links to the 2004-2006 award winners. Also, there's a Picture of the Week feature on the site that might interest you.

Kind thanks to edgeplot@Flickr from Seattle, Washington for this intriguing photograph (original image | BPotD Flickr Group Pool). edgeplot took this image at the beautiful Deception Pass State Park in Washington. Thank you!

If you visit the original Flickr posting, you'll note that edgeplot titled this image “Parasitism in the Salt Marsh”. I prefer an alternative, more Hollywoodish title: “The Halophyte and The Parasite”.

Salicornia virginica, or pickleweed, is the halophyte. If you're confused as to which plant is the Salicornia, it is the green plant with thickened stems – see this photograph for a parasite-free version. It is able to grow in highly saline environments, such as this salt marsh, through its ability to sequester salt into the vacuoles of its cells. For an explanation of that adaptation, see this page on pickleweed (via Great Salt Lake Playa Ecology). The reference refers to a different taxon, but the mechanism should be the same.

The parasite is Cuscuta salina, or salt-marsh dodder. As edgeplot succinctly explains, “The dodder has twining orange stems and creamy white flowers. It is parasitic and unable to photosynthesize, and lives off nutrients taken from its green pickleweed host.” A short summary about dodder is available from the lab of Dr. Colin Purrington: background on the genus Cuscuta (dodder).

Botany resource link: Fruits and Seeds is a chapter in “Botany Online – The Internet Hypertextbook. Features magnified fruit images illustrating structures aiding seed dispersal.

A thank you to van+s@Flickr (original image | BPotD Flickr Group Pool) for sharing today's photograph, taken inside a greenhouse at New York Botanical Garden.

One look at this photograph of the boojum tree and I was immediately reminded of my image of Fouquieria splendens. Makes sense, I suppose – they are (now) both in the same genus. However, a search for Idria columnaris yields two-thirds the results of a search for the current scientific name, so this synonym is still often used. At least in one sense, it is too bad that this species has been moved into Fouquieria: Idria is far easier to spell.

The Virginia Tech Forestry has a factsheet on Fouquieria columnaris that is worth visiting to see more of this plant. I particularly like this quote: “VERY UNUSUAL, considered by many to be the strangest looking tree on earth.”. The University of Wisconsin Botany Department has some photographs of this species (of a decent size) showing its habit: Fouquieria (ignore the photo that is titled F. columnaris Flowering Plant – it is actually Fouquieria splendens).

If you have access, you might want to read the following for a detailed examination of the biology of this species: Humphrey, RR. 1933. A Study of Idria columnaris and Fouquieria splendens. Am. J. Bot. 22(2): 184-207.

Photography resource link: I don't often link to camera gear because it seems too many photographers get distracted by the tools instead of taking photographs, so I deliberately try to avoid it (except when I'm researching techniques and learn that I need a different tool). However, I have to make an exception for this: the Seitz 6 x 17 Digital – 160 megapixels scan back camera that can capture an image in 0.5 second (a scan back camera operates more like a scanner, so you have to imagine a really fast, super high-quality, portable scanner with the depth of field of a camera). And for only the low, low price of 28900 Euros or ~ 37000 USD. Fun to imagine in idle moments.

bbum@Flickr, aka Bill from San Jose, California, contributed today's photograph (original image | BPotD Flickr Group Pool). Thanks again, Bill – I appreciate the contribution to this month's occasional theme of orange and green (and sometimes white) on BPotD.

I'm not able to tell from this image or Bill's other photographs of this marigold field as to whether these are a cultivar of Tagetes patula or Tagetes erecta, but perhaps someone more expert will make a suggestion. In either case, though, these bright plants have a common name in Mexico that is anything but bright: la flor de la muerte, which translates to “the flower of death” (according to Allan Armitage in his “Manual of Annuals, Biennials and Half-Hardy Perennials”). Unfortunately, Dr. Armitage does not explain the reason for that moniker. Speaking of names, I should also note that the common name “marigold” outside of North America often refers to members of the genus Calendula.

Dr. Armitage notes that the roots of some species produce allelopathic compounds, which can suppress certain weeds. For this reason, and the fact that they can also deter some unwanted insects, Tagetes are sometimes used in companion planting.

Botany resource link: Flora brasiliensis is a project to first digitize the 1840-1906 textual work containing nearly 23000 Brazilian species and then update the information. The site can be a little difficult to navigate, but viewing some of the line drawings can be very rewarding (sorry, I'm not able to link to any images directly).

If you'll recall my reaction to the fragrance of the Schima flowers, imagine the opposite reaction when smelling my fingers after squeezing the inflorescence of this plant, blue sage or rose sage. It is quite disgusting (I believe the word “foul” was used), and the smell lingers for some time; it is far better to appreciate this southwestern US and Mexico native for its appearance.

There seems to be some interesting evolutionary biology and taxonomy surrounding Salvia pachyphylla and the closely-related Salvia dorrii, but I haven't been able to track down a published peer-reviewed paper on the subject reflecting modern work. This abstract of a presentation at one of the Botanical Society of America's annual Botany Conferences piqued my interest: The Phylogeny and Adaptive Radiation of Salvia pachyphylla (Lamiaceae).

CalPhotos has a number of images of Salvia pachyphylla if you'd like to browse through more. You could also read the entry in the Jepson Manual about this plant for a description.

Photography resource link: for inspiration, the photography of Tomas Kaspar. You can also view a selection of his images on Flickr: Tomas Kaspar.

The garden originally received this plant as a propagule of a plant collected in the state of Nuevo León, Mexico. Bidens heterophylla was the name attached to the plant at the time, a name which the USDA Plants Database reports is a synonym of Bidens aurea. It is commonly known as Arizona beggarticks (or Arizona beggarstick), even though the vast majority of its range is in Mexico.

From what I can tell, Bidens aurea is a highly variable species. The description of the plant in the Flora of North America (see Bidens aurea) uses many parentheticals to denote that the plant's morphological properties can vary extremely from the norm, e.g., disc florets 12–30(–60+), meaning that the number of disc flowers (the ones in the centre of this composite flower) typically range from twelve to thirty, but over sixty can be found in rare plants. More evidence of variability can be seen online using an image search: Bidens aurea, including these two illustrations, 1 and 2. Despite the poorly-known scientific names on these illustrations, both are apparently synonymous with Bidens aurea (images and synonymy via the Universal Library Compositae page).

I do have to admit to being a bit skeptical that this is all one species based on the extreme differences in morphology, but I've not found anything suitably authoritative to contradict it. Particularly curious is that the FNA treatment does not describe the plant as having nearly-white ray florets, but it's within the realm of possibility that this plant was selected for that very reason (its different flower colour).

Botany / horticulture resource link: Bamboo Research through Washington State University's Extension Unit. The site leans to local resources, but also includes a number of links that are relevant anywhere bamboo will grow.

A kind thank you to Margaret Morgan of Sydney, Australia for sharing today's image. You can see Margaret's preferred crop of this image on this page, but she gave me permission to select a different crop for one of the standard sizes I use for BPotD (so thanks again). I enjoy Margaret's web site quite a bit (since I seem to agree with her on many things), so you might like to visit it as well: Margaret Morgan. Much appreciated, Margaret.

The common name for this orchid is yet another of those lateral-thinking-required misnomers ̵ rock lily. I suppose it is relatively easy to see a superficial resemblance to a lily inflorescence when looking at the mass of flowers. A closer look at each individual flower, however, reveals it is indeed an orchid (and to be fair, some sites do suggest “rock orchid” as a preferred common name).

The “rock” part of the common name is entirely fitting, however. Dendrobium speciosum is often found growing on rocks (hence it is a lithophyte), though it can also be epiphytic (growing on other plants). It is known as one of the showiest orchids in the world, as I'll assert is well-detailed by Margaret's second photograph.

Two excellent pages worth investigating if you'd like to learn more are Dendrobium speciosum from the Association of Societies for Growing Australian Plants and the Dendrobium speciosum complex from the Australasian Native Orchid Society.

Photography resource link: I continue to enjoy Alain Briot's essays: Of Cameras and Art via The Luminous Landscape. Also, read the follow-up essay from one of his readers, David White.

I was excited about having another BPotD “exclusive” to share with you today, i.e., a species that doesn't appear on search engine image results. Unfortunately, I was scooped on this one: “growin”, a member of one of the web's largest gardening sites, posted a few photographs of this particular plant a week ago (though I'll note that he did have to walk in the bed to get these photographs, something not encouraged for garden visitors). Small consolation, perhaps, but today's BPotD pics at least seem to be the first few photographs of this plant in flower on the web.

Taking the time to smell the flowers elicited an “oooooo” from me. I thought it smelled of a sweet vanilla; Douglas thought it had elements of banana. We both agreed, though, that the fragrance was fleeting – you could only smell it for a brief time before becoming desensitized to it.

A native to the Yunnan province in China as well as Tibet, Schima sericans was published as a species in 1997. The draft treatment of the Theaceae in the Flora of China agrees with the assessment of this as a separate species segregated from the (slightly) more common Schima wallichii. Despite some reservations about the assertion that this is one of a number of closely-related species (instead of much morphological variation within a single broad species), we're treating it as distinct for the time being at UBC.

A big thank you again to Eric in San Francisco (Eric in SF@Flickr) for offering today's image via the BPotD Flickr Group Pool (original image). An intriguing pattern expertly captured, Eric – thank you!

I believe this is the fourth member of the Crassulaceae to be featured on BPotD, preceded by Dudleya pulverulenta, a cultivar of Aeonium arboreum and Sedum spathulifolium. If you visit those pages, you'll note that a pattern emerges – most of the Crassulaceae are succulents.

Although this particular plant is being cultivated in the Strybing Arboretum in San Francisco, this species is actually native to southern Africa, where, like many succulents, it grows in an arid environment.

For local readers, you might like to visit Riverview in Coquitlam to attend this year's Treefest today (rain or shine!). This event celebrates the nearing-a-century-old arboretum on the grounds of the Riverview Hospital. See the web site of the Riverview Horticultural Centre Society) for more information about this heritage site that is not yet permanently protected from “development”.

I did mention in the previous entry on Lobelia tupa (or devil's tobacco) about my desire to take a different photograph of this species. Here it is!

Only a brief entry today - apologies. After checking out this abstract photograph of a pattern on the bark of a silver acacia, though, you can spend a lengthy piece of time reading this fascinating article on acacias from Wayne Armstrong: The Unforgettable Acacias. It spans everything from seed dispersal (by ants) to commercial products (gum arabic).

The Plants for a Future database also has an entry on this southeastern Australian tree: Acacia dealbata Also, please note that it is invasive in southern California.