Seventh in the series on Australian plants comes to us courtesy of Eric in SF@Flickr (original image) via the BPotD Flickr Group Pool). As always, it's appreciated, Eric.

Despite resembling plasticky four-leaf clovers, these are actually aquatic ferns. The strong resemblance, though, is reflected in some of its common names: water clover or floating water clover. It is also known as the banded nardoo.

This is a plant of ponds and riverbanks throughout most of Australia, including Tasmania. The flat, broad leaves are representative of one of the two typical leaf morphologies for aquatic plants. Large, flat leaves aid in both flotation and optimal capture of sunlight, and are often found at the water surface. The second typical aquatic leaf form of submerged, fine, narrow leaves is not observed in Marsilea (for an example of such, see Elodea)

Photographs of the plant in habitat can be seen on the New South Wales Flora Online: Marsilea mutica.

Today's image is courtesy of Van in NYC@Flickr (original image | BPotD Flickr Group Pool). Van in NYC took this tilted photograph at the Santa Barbara Zoo – it's worthwhile to note that zoos often have extensive botanical collections. Thanks again, Van in NYC!

It's a holiday Monday, so just a few links for an entry today. The Australian National Botanic Gardens provides an excellent information sheet on this New Guinea and Australian native: Growing Platycerium bifurcatum. If you're interested in some of the biology behind staghorn (or elkhorn) ferns, see: Kreier, H and Schneider, H. 2006. Phylogeny and biogeography of the staghorn fern genus Platycerium (Polypodiaceae, Polypodiidae) (abstract, if the full article isn't available). American Journal of Botany. 93:217-225.

For a humourous staghorn fern, see this BPotD submission: Staghorn Fern Bug? (thanks, toutlan!).

Photography resource link: National Geographic has a section on their web site dedicated to photography, with many photo galleries to explore if you've some time!

I couldn't resist sharing today's photograph in both vertical and horizontal orientations. The correct perspective is the vertical, since this is a cliff with seeping water. Still, I imagine the horizontal image could be used to trick more than a few people.

The challenges of the vertical environment for plants include exposure to wind and sun, poor or lacking soil, nutrient availability and gravity. These factors would be studied by cliff ecologists; cliff ecology is a specialized discipline within ecology that examines and studies organisms of cliff environments and how they interact with each other and the physical environment. Never heard of cliff ecology? A book review for “Cliff Ecology: Pattern and Process in Cliff Ecosystems” explains why. Here's the lede of the review: “Question: What is vertical, predominantly rock, virtually unstudied and largely taken for granted by land managers? Answer: A cliff. Perhaps no other landscape feature has been so consistently ignored despite being pervasive and prominent across the world. Ecologists haven't studied cliffs, and land managers haven't assumed responsibility for protecting them.”.

Two of the three vascular plants I noticed growing on this particular cliff face are in this photograph: Adiantum aleuticum and Saxifraga mertensiana (I've yet to ID the third, but it is not in this image). If I had to identify the moss, I'd hazard a guess and suggest it is Hypnum subimponens (Hypnaceae). This tentative ID is based on environment (seeping cliffs), habit (mat-forming), and colouration (yellow-green new growth, brownish-green in older areas) via the description in “Plants of the Pacific Northwest Coast” by Pojar & MacKinnon.

Photography / agriculture resource link: International Plant Genetic Resources Institute's Image Bank contains images on the subjects of plant and crop diversity (my favourite is this photograph of an orange-fleshed banana).

The unfurling fronds of Western maidenhair fern in dim, morning light look little like the mature fronds in indirect sunlight.

The distribution of Adiantum aleuticum (map) is a case study in disjunct populations, or populations of a species separated by a wide geographic or ecological distance. Broadly speaking, western maidenhair fern's main distribution range is coastal and inland forests of Alaska south to California. However, as mentioned by the Flora of North America account for the species, it is also “disjunct in wet rock fissures at high elevations in Arizona, Colorado, Montana, Nevada, Utah, Wyoming, and Mexico in Chihuahua, and it is disjunct on serpentine in Newfoundland, Quebec, Maine, Maryland, Pennsylvania, and Vermont.” Your task of the day is to generate a possible explanation for the pattern of this plant's distribution, particularly for its disjunct populations (the map link above gives a clear overview of the distribution).

Landscape architecture / horticulture resource link: Dr. Peter Del Tredici from Harvard University's Arnold Arboretum has two articles worth reading in the February 2006 issue of Landscape Architecture. The first, titled “Because Plants Are At Stake” (PDF), addresses the importance of having a knowledge of plants in the field of landscape architecture. The second, “Brave New Ecology (PDF)”, tackles the question “Can we ever put the invasive species genie back in the bottle, or are we looking at a future in which nature as we know it becomes a cultivated entity?”

I'm on vacation, so only a short written accompaniment today. – Daniel

Lip fern, or lace-lip fern, is native to western North America, from British Columbia south to California and east to Montana. Given the diversity of environments within that large area, it is not surprising that it isn't found everywhere within the region. Using Cheilanthes gracillima as an example, here's a small survey of how different databases present the distribution information.

The USDA's PLANTS database operates on a state-by-state presence/absence mapping system, like so: Cheilanthes gracillima. While useful in a broad context, it isn't very precise; if you make the assumption that you might find the plant in eastern Montana or south of the California border, you will be searching for a very long time.

The Flora of North America improves upon the PLANTS map by delineating the extent of the distribution: Cheilanthes gracillima. If you are familiar with regional geography, these types of maps can often give some hint as to what limits the distribution of a species. For this fern, it seems it grows in hilly or mountainous areas that are not subject to extreme heat or cold.

That presumption seems to be borne out by examining both the county-by-county distribution map in Washington state and the Jepson Manual's distribution map in Californian Floristic Provinces. These distribution maps allow better inference about the habitat and ecological requirements of the species, particularly the Californian map as it uses ecological similarities for map subdivisions.

A different approach is taken by the British Columbia E-Flora Atlas Page for Cheilanthes gracillima, which uses point data to map the location of documented collections of the plant (i.e., herbarium specimens). Interestingly, you can add to the map the “BEC Zones” (or Biogeoclimatic Ecosystem Classification) layer (similar, though not equivalent to the California Floristic Provinces) and discover that lace-lip fern is found in a half-dozen or so different ecological regions in British Columbia, but only one or a few known records of Cheilanthes gracillima exist for each region. In all of the other distribution mapping schemes, the notion that this species is relatively uncommon is masked by the presentation of the data.

I'm on vacation, so only a short written accompaniment today. – Daniel

The Herbarium at the Rancho Santa Ana Botanic Garden has an excellent article on Dryopteris cycadina, or shaggy wood-fern.

This image of Wallich's wood fern was taken in May, 2005. For a gardener's perspective on it, I'll direct you to Paghat's Garden. For (many) more photographs, have a look at the Hawaiian Ecosystems at Risk Project's native plants entry on Dryopteris wallichiana.

Like previous black and white images this month, I've used the Photoshop Calculations command. On this image, I combined the red and blue channels with screen at 100%, then the red and alpha1 channels using multiply at 85%. Since this probably means very little to you if you don't have Photoshop, I've uploaded the set of black and whites (red, blue and green channels, and the intermediary alpha1 channel) in one large image – you can see it here. At the very least, you'll see that there are a number of black and white manipulations that can be done to an image digitally; then again, many of the same manipulations were possible with film, depending on what film one used and what technique one used to develop it.

Botany / travel resource link: I believe someone mentioned this link on the garden's forums or the BPotD comments, but in case you missed it, check out Conifer Hunting in Mexico, a travelogue via the conifers.org site.

This is the Taiwanese variety of Oriental chain fern, collected in the mountainous forests of Taiwan by Dan Hinkley in 1999. The common name is derived from the chain-like arrangment of sori (spore-producing organs) on the underside of the leaves (not seen here).

As I find this plant both structural and photogenic, I've taken a number of photographs of it in the past. Other attempts can be seen here: Woodwardia orientalis var. formosana via the UBC Botanical Garden Forums.

A few notes of interest regarding Botany Photo of the Day:

• A warm welcome to readers of GardenWise. Starting with the Fall 2005 magazine, GardenWise will be highlighting an entry or two from Botany Photo of the Day in each issue, helping us promote both the science and beauty of plants.
• Richard Dickey of Feral Flowers sent a note of thank you regarding the entry on Eschscholzia californica, so I've posted it as a comment - worth checking out.
• Tangled Bank, Issue Number 35 is out, hosted by Cognitive Daily. Tangled Bank is a “blog carnival” - a periodic collection of links to different weblogs based on a certain theme. In the case of Tangled Bank, the theme is science, so follow the link and see some of the best of what other science-themed webloggers are writing about.

Photography resource link: Converting Images from Colour to Greyscale. Darwin Wiggett explores some techniques in Photoshop for converting colour images to greyscale. I've used the “Blending Two Channels” technique for today's photograph, with a red-red channel multiplication at 100%.

Once thought to be a single widespread North American species, Adiantum pedatum (maidenhair fern) was recently segregated into three - the eastern Adiantum pedatum, the western Adiantum aleuticum and (known only from Vermont) Adiantum viridimontanum. Although the similarities and differences between Adiantum pedatum and Adiantum aleuticum have been recognized in the past (the western taxon sometimes being known as Adiantum pedatum subsp. aleuticum), reproductive isolation (they don't interbreed) and the number of morphological differences drove the decision to ultimately split the traditional species up.

Photographed in UBC's Native Garden, site of a good collection of Pacific Northwest ferns.

While in the Asian Garden yesterday documenting some of this year's plant inventory at the garden, I decided to try photographing this lovely little fern yet again. I've attempted it previously, but was never happy with the results.

I'm happy with this, although the photograph at this size still doesn't capture the flow and subtle beauty of this gem. So, for the first time for the Botany Photo of the Day series, I'm supplying the full-size version of a photograph, Adiantum venustum, for you to see. Be warned! The file is 3 megabytes in size - if you are on dial-up, go fetch a cup of coffee or tea. Unfortunately, the file opens to the weakest spot in the photograph (the upper left) - make sure you scroll down and to the right to be appreciating the same things I am with the plant.

Apologies for being light on the science side of things today - as I mentioned in a previous post, my time is elsewhere this week with the inventory. I do have the energy for a small story, though. I wanted to thank everyone who attended the Perennial Plant Sale on the weekend - the event was a huge success. I know that at least a few readers of Botany Photo of the Day attended, because I had an opportunity to speak with the Friend of the Garden who was volunteering in the “Tender Plants” section yesterday evening. She admitted to me that she hadn't visited the web site recently, and could not figure out why so many people were asking for Salvia discolor, which was featured as the Photo of the Day last Saturday. Once she figured out it was because of the web site, she was pretty impressed. So, thank you to those who live locally and who were inspired enough to seek out Salvia discolor based off that photo entry; if you did attend the sale hoping for a Salvia discolor but were disappointed, I hope the thousands of other plants available partly made up for it.