Acer macrophyllum “Bigleaf Maple” Aceraceae, with
Laburnum anagyroides “Golden Chain Tree” Fabaceae
May 30, 2012
The largest leaves on Bigleaf Maples easily reach 2 feet in length! These trees are keystone species in riparian zones throughout the wet lowlands of the PNW and are particularly important for sustaining healthy moss populations. In the background, you can see the bright yellow flowers of the introduced Golden Chain Tree. These papilionaceous flowers (in the pea family) are favored by bumble bees which are large enough to wriggle their way into the corolla.
Populus tremuloides “Quaking Aspen” Salicaceae
Apgar Lookout Trail, Glacier National Park, MT
October 9, 2015
This adorable Quaking Aspen sapling had lost all but three of its leaves by the time I photographed it in early October. While Quaking Aspen is famous for its adventitious, clonal reproduction, this little guy probably grew from seed because it was all alone in the at the edge of a stand of conifer saplings. Seedlings in the genus Populus are often the first to colonize abandoned mining sites that are too toxic for other species. Recent research suggests that they are only capable of this feat because of a mutualistic relationship with various species of mycorrhizal fungi such as these earthballs.
Acraspis macrocarpae “Jewel Oak Gall Wasp” gall, Cynipidae
October, 21 2015
Female jewel wasps are adorable, wingless, pudgy little things when they emerge from these galls in October. Here’s another picture of these cuties for good measure. These unique organisms reproduce in cycles of alternating generations of all females and generations with both sexes. In years with only females, the wasps reproduce parthenogenetically. Apparently, parthenogenetic galls are different in size, shape, and color than their sexually-produced counterparts. I was unable to find specific information regarding this phenomenon in Acraspis macrocarpae, but most accounts suggest that only females occur inside these particular galls, which leads me to believe they may be the sexually-produced versions of these oak galls. Perhaps next year, we’ll see a completely different variety of gall on our local oaks! I’ll be sure to update you all next fall.
Also, fun fact, this species of gall wasp was originally described by Alfred Kinsey, the world-renowned human sex scientist! It’s true! Before studying sex, Kinsey collected more than 7.5 million galls and wasps and named dozens of species. Of the 18 million insect specimens currently housed at the American Museum of Natural History, nearly a third are from Kinsey’s dissertation! His work not only revolutionized our understanding of this wasp family, but also had profound impacts on the ways we conducted phylogenetic and entomological analyses. Read more about his fascinating work as an entomologist here.
Gymnosporangium globosum “Cedar-Hawthorn Rust” Basidiomycota
October 23, 2015
I first noticed these strange tendrils on the underside of Hawthorn (Crataegus douglasi) at a city park a couple months ago, but only just got around to photographing them. I thought they might be some sort of aphid galls after noticing that the leaves were covered with the insects. But the truth, it turns out, is far more spectacular! This is actually the fall life-stage of a rust fungus that infects Cedars (and Junipers). The fungus overwinters on Cupressaceous conifers, producing a small gall that grows large, orange gelatinous horns after spring rains. These jelly tentacles release spores that then infect the leaves of Rosaceous trees and shrubs such as Crataegus, Malus, and Sorbus. By late summer, fungi on these Rosaceous hosts produce the large porcupine-like clump of tendrils seen here. These tendrils release more spores that continue the cycle anew! I’m in love. What a phenomenal fungus!
Populus trichocarpa “Black Cottonwood” Salicaceae
Clark Fork Natural Area, Missoula, MT
October 23, 2014
The brilliantly yellow trees lining our valley bottoms and riversides here in the Pacific Northwest are predominantly Black Cottonwoods (also known as Western Basalm Poplars). They are famous for their fluffy, cotton-coated seeds which fill our air and waterways throughout the early summer. These seedlings need moist, bare soil to germinate and will rapidly colonize riverbanks exposed by erosion. Seedlings become dominant, fully-grown trees after about 25 years making them ideal for cultivation both in farms for harvest and as ornamentals in neighborhoods. Unfortunately, they also rarely live more than 150 or 200 years, so many neighborhoods in our area (many of which were first constructed in the 1800s) are being forced to remove these dying giants.
Snowberry (Symphoricarpos albus) clinging to the last days of summer
Apgar Lookout Trail, Glacier National Park, MT
October 9, 2015
While brilliant fall colors are normally the highlight of dreary October days here in the Pacific Northwest, there’s also something to be said about the subtle beauty of bare branches. These ghostly grays criss-crossing in a spider web of angles and arcs provide an enchanting, textured backdrop in a world that is slowly dying and preparing for winter.
Fossil Maple Leaf, Winthrop Formation
Mid-Cretaceous (110 mya)
In honor of National Fossil Day, here’s a neat fossil from the Winthrop Formation in north-central Washington. This species looks very similar to modern day maple species, but has yet to be formally identified. This particular fossil formation is rife with beautiful plant specimens. By studying the morphology of these fossil leaves, we can estimate the mean annual temperature of the region 110 million years ago. Using this method, scientists estimate that mid-Cretaceous Washington was almost 12 degrees (˚C) warmer than it is today. (Specimen courtesy of the University of Puget Sound, Geology Department)
Fall is in full swing here in Montana!
I made it up to Glacier National Park this weekend to experience some fall foliage firsthand. It was absolutely stunning!
Here’s a brief guide to foliage colors in Western Montana!
- Members of Salicaceae (Cottonwoods, Aspens, Poplars, Willows) and Betulaceae (Alders, Birch) dominate the yellow palate of our PNW hillsides. These species begin turning in September and their colors will persist, depending on rain and wind, until late October.
- Larch (Larix) is our only deciduous conifer in the PNW. Depending on elevation, Larch will begin turning between the first and third weeks of October.
- Bracken Fern (Pteridium aquilinum) and Thimbleberry (Rubus parviflorus) also maintain a substantial degree of yellowness early in the fall before turning pale brown in October.
- Red fall foliage in western Montana is largely restricted to the understory.
- Ericaceous shrubs such as Huckleberries (Vaccinium) change color depending on sun exposure. On exposed hillsides, they’ll be red before August, while in dense forests, they may only begin changing in October.
- Rosaceous shrubs such as Oceanspray (Holoduscus), Ninebark (Physocarpus), Spiraea, Hawthorn (Crataegus), and Rose (Rosa) also tend to go through a red phase in their color change. While some of these species appear to start early (September), most of their change will persist well into October and even November.
- Red-osier Dogwood (Cornus sericea) has an interesting color change. Here in the riparian areas of Western Montana, they appear to go through a green and maroon phase, which is quite lovely, before losing their leaves entirely. Fortunately, even after losing their leaves, these shrubs have phenomenal red stems that definitely supplement the colors of fall.
- Maple (Acer) also go through a red phase here in western Montana. These native species appear to have dropped most of their leaves by mid-October.
Species with little color change:
- I’ve noticed several dominant deciduous trees and shrubs that don’t appear to change color considerably with the seasons. Of these, Ceanothus and Symphoricarpos are the most abundant.
- Ceanothus tends to keep its green foliage throughout the year or turn straight to brown in the fall.
- Snowberries (Symphoricarpos) appear to do a variety of things, but here in western Montana, they generally drop their leaves quickly without much ado.
Holodiscus discolor “Oceanspray” Rosaceae
Mt. Sentinel, Lolo National Forest, MT
September 12, 2015
Oceanspray is one of my favorite plants here in the PNW. It’s a modest-sized shrub that grows foamy white inflorescences that brighten up nearly all open hillsides west of the Rocky Mountains in the spring. These inflorescences are long-lived and fade to a creamy beige that contrasts nicely with their rich green foliage throughout the summer. In the fall, Oceanspray leaves begin changing early in the season and progress through a rainbow of colors until becoming a uniform maroon-scarlet after the first frosts of October. These plants have a very tough wood that is resistant to fire and are regularly the first plants to recolonize areas following a burn.
Speyeria hydaspe “Hydaspe Fritillary” Nymphalidae
on Agastache urticifolia “Nettle-leaf Giant Hyssop” Lamiaceae
Great Burn, Lolo National Forest, MT
July 10, 2015
Fritillaries are a common, large butterfly here in the PNW east of the Cascades. There are several species that are regularly found in our area. Learn more about them here. This particular fritillary is feeding on the nectar of a very interesting and quite common local plant. Its Latin name, Agastache, is Greek for “many spikes” and, as you might guess, its inflorescence looks like a giant spike ball. Like many other members of the mint family, giant hyssop is commonly used in herbal teas and poultices for a variety of medicinal purposes. In particular, the leaves can be used to induce sweating and as a vasodilator. This particular species is quite abundant in the PNW east of the Cascades and is a favorite food source for many ungulates like deer, elk, cows, and moose.