Thursday, September 27, 2012

The Cornus Conundrum

Species name: Cornus capitata

Common name: Himalayan dogwood

Location: Ontario

Despite this looking a whole lot like the Japanese Dogwood in a previous blog post (also called the Chinese dogwood; read all about it HERE), I believe very strongly that this is a different species; at least, that this individual tree would be classified as a different species according to currently recognized species. Whether or not a DNA analysis would confirm or deny that these are, in fact, two separate species is probably up for debate. I think the key here lies in the fruit and in the leaves.

The fruit of the Japanese dogwood is quite dense. Once you get through the tough outer rind there is a a sweet flesh on the inside, but not much of it because the seeds are quite large in comparison to the size of the fruit. In the Himalayan dogwood (native to, you guessed it, the Himalayas where it is not overly common), the fruit is much larger, much juicier, but also much less sweet. This series of photographs is actually of my neighbour's tree (I'm glad they don't question me sneaking around the front of their property, taking pictures of their plants!), and I'll be the first to admit that I tried one of the fruits. It was bad. Really bad. The Wikipedia page of the Himalayan dogwood doesn't say anything about the fruit being tasty (it does say edible but bitter, which would be spot-on based on my experience; read the entire paragraph worth of information about it HERE), but I figured at the time it was worth a shot. I don't recommend it.

The leaves of the Japanese dogwood have rather non-descript borders, exactly as you would imagine from a dogwood. Smooth leaves on the top and the bottom, a prominent primary vein down the centre of the leaf with equally prominent secondary veins coming off of that running almost to the leaf edge, and very few easily visible tertiary veins. The Himalayan dogwood is quite similar, except that the leaf edge is a much lighter colour than the rest of the leaf and almost provides a border around the outside. When felt, the leaves of the Himalayan dogwood are also much hairier than the Japanese dogwood (which have very glossy, green leaves).

The Himalayan dogwood, whether on purpose or by accident, is gaining popularity as an ornamental plant in North America. It is much more cold-tolerant than its Japanese relative so is more favourable for slightly more northern climates. Don't expect it to survive in Alaska, however; it's not quite that cold-tolerant! The fruit of the Himalayan dogwood are also much showier than the Japanese dogwood, providing a spectacular show in the fall, and have very similar showy inflorescences in the spring. Because the fruit is so much more bitter, it doesn't have the sugar content required to be of great use in the winemaking industry (like in which the Japanese dogwood is sometimes used) and for the same reason is much less edible. The flip side of this is that it is much less appealing to herbivores and so the fruit remain on the tree until they rot (and provide an equally spectacular odor; picture the smell of fermenting, rotting apples in an orchard on warm days in the fall...). There are some species of insect that will consume the fruit, but these are relatively few.