Many thanks to Lotus J. aka ngawangchodron@Flickr for sharing today's photograph with us (via BPotD Flickr Group Pool | original image) – appreciated, as always.
How many species of Crataegus (or hawthorns) exist? The answer is, “It depends on what you mean by species.” Depending on the taxonomic interpretation, there may be a couple hundred species or there may be over a thousand. Charles Sargent, first director of the Arnold Arboretum, described 732 new species. Dr. Tim Dickinson of the University of Toronto cites W.H. Camp as pronouncing the determination of number of species as “The Crataegus Problem”.
Dr. Dickinson provides excellent resources about hawthorns on his lab and teaching site. A broad description of hawthorns is available on this page: Crataegus. A paper specifically about the black-fruited hawthorns (of which Crataegus douglasii is one) can be found here: North American Black-Fruited Hawthorns.
Landscape architecture / art / design resource link: Pruned, recently listed as one of the Best Blogs of 2006 That You (Maybe) Aren't Reading. Hours and hours of readings and wanderings available here.
Crataegus douglasii - Z5 - Index of Garden Plants, Griffiths
Have you read the book by James Phipps with Robert J. O'Kennon and Ron W. Lance. 2003. Hawthorns and Medlars. RHS Plant Collector, published by Timber Press?
It is well worth a read!
Best wishes,
Michael
Good idea, Michael - I think that's another book that's on the garden's “Wanted” list.
"about the black-fruited hawthorns (of which Crataegus douglasii is one)"
. . . the fruit in the photo look very red to me - is the identification of the plant in the photo correct?
Distributionally, there isn't anything else it is likely to be – unless it isn't native. Some of the older fruits are blackish-purple, so I'm not uncomfortable with the ID, particularly knowing that the taxonomy has been so confused for so long.
"unless it isn't native" - to be honest, I'd not be able to tell this (sans leaves) from my native (your invasive) Crataegus monogyna. I can't see anything that excludes that species.
I noticed the darker fruit, on a close look, they are all damaged (skin split) or partly dried out, so probably fermented (damaged C. monogyna fruit look like this, too).
There was something in Maryland Growing up called "poke berries " that look like that with dark on the outside with magenta juice I used to paint with it.
I'd have to agree it looks more like C. monogyna, which can be invasive in the PNW. It was widely planted (and naturalized) in Oregon when I lived there a decade ago.
Plus it hybridizes with douglasii, to further complicate matters.