According to Kew’s State of the World’s Plants report, approximately 2000 species of flowering plants are described as new to science each year. Most of these are from Brazil, China, and Australia. For Canada, somewhere between 0 and 9 new species have been described each year between 2004 and 2016. Castilleja victoriae was one of Canada’s nine species in 2007.
Many newly-discovered species in well-botanized areas of the world are somewhat cryptic–they look similar enough to a known species that most observers would simply assume they are the same, or, at best, a minor variation from the familiar. For these hidden species, trained eyes and taxonomic expertise are required for discovery. Such was the case with Castilleja victoriae, which had first been collected for Western science in Victoria, British Columbia, Canada by John Macoun in 1893. It was ascribed to (what is now known as) Castilleja tenuis at first. In 1941, it was re-assigned to (again, what is now known as) Castilleja ambigua subsp. ambigua. Under this name it hid until 2005 when botanist Matt Fairbairns compared live material of Castilleja ambigua subsp. ambigua from western Vancouver Island with plants from Victoria’s Oak Bay area. After documenting the differences in morphology and ecology, he consulted with one of the world experts on Castilleja, Mark Egger (who also happens to be an occasional BPotD contributor and commenter!). Accumulating the necessary evidence over the next two years to make a convincing case, in 2007 the two gentlemen published “Castilleja victoriae (Orobanchaceae): a New Rare Species from Southeastern Vancouver Island, British Columbia, Canada, and the Adjacent San Juan Islands, Washington, U.S.A.” in Vol. 54 (pages 334-342) of Madroño.
Castilleja victoriae, or Victoria’s owl-clover, is a small annual species, ranging in height from 2 to 20cm (1-8 in.). In terms of habitat (from the Species At Risk Assessment for Victoria’s owl-clover (PDF), it
is restricted to vernal seeps and the margins of vernal pools within 50 m of the shoreline, where oceanic influences lessen the frequency and severity of winter frosts. These sites are saturated or inundated for much of the winter and early spring and are very dry by early summer. The extreme growing conditions, and the shallow soil in which Victoria’s Owl-clover grows, greatly restrict competition from native species. The most common native plants that co-occur with Victoria’s Owl-clover are spring ephemeral annual herbs. A number of non-native species have become common and often dominate the habitat type favoured by Victoria’s Owl-clover.
Historically, it has been collected from 8 (or 9) different sites in Canada. Four (or five) of these are no longer extant, with populations being extirpated due to urbanization and habitat degradation. The site with uncertainty is an instance of lost documentation, but it seems to have been historically unlikely based on known habitat requirements. Of the four remaining sites, several are under threat from recreational use. From the PDF linked above:
Recreational activities are another major threat to Victoria’s Owl-clover. Oak Bay Population #2 receives heavy foot traffic throughout the year, largely from local residents and weekend visitors from elsewhere in the Victoria area. Some plants have been crushed by walkers, others have been damaged when picnics have taken place on top of them, an illegal fire-pit was constructed on the population in 2004 and a local resident used the area to practise his golf swing in 2003 (removing large divots). Considering the small area occupied by the plants, this level of use poses a serious threat.
Oak Bay Population #3 receives extremely heavy foot traffic in spring and summer, when tour buses bring hundreds of visitors each day. There is also heavy foot traffic throughout the autumn and winter, along with dog-use and bicycle traffic. As a result, in 2002 and 2003 a significant proportion of the plants in this small population were crushed before they could produce ripe fruit. The recreational use has also led to habitat degradation, as soils in the vernal pool were both compacted and eroded.
This latter population (#3) has also seemingly been extirpated in the past decade, leaving the species with three populations in Canada and one population on a San Juan Island in adjacent Washington state. Today’s photographs are from the largest known population in the Trial Islands Ecological Reserve, where plants occupy a space totaling about 600m2 on the main island–about 15% of an acre. Special research permission is needed to visit the Reserve, as there are several sensitive and rare plant species present. Accompanied by Matt Fairbairns, three of us from UBC Botanical Garden assisted with plant counts for some of the sensitive species in bloom.
Only a few plants of Castilleja victoriae were in flower, and I was extremely mindful of where I positioned myself for photographs, so I only had limited options for both photo composition and selection of which plants to photograph. You will find the photographs available via E-Flora BC’s gallery of Castilleja victoriae more comprehensive and perhaps more compelling. Fortunately, as you can see in my image of the habitat, there was “bare” rock adjacent to the two hundred or so purplish-brown individual plants in this depression. I was able to take photos from near ground-level without having any potential impact on the population. The rock wasn’t truly bare, though–it had an extensive lichen flora nourished by deposits from birds. It also had current deposits from birds, but one tells oneself “it’ll wash off” before rolling around on such things for BPotD photographs.
Also on a BPotD note, the June 2005 entries have been updated/corrected–interesting to revisit these, as it was the month when the weblog became Yahoo!’s site of the day and received a heavy boost of traffic and comments.