Corallorhiza Trifida, Northern Coralroot

Day 222: An unexpected call took me out in the field with my botany partner Joe yesterday. He'd found three more stems of Corallorhiza trifida, the plant I had failed to find last week. Trifida is a member of the Orchid family, and is one of our favourites. While it is not scarce enough to be considered rare, it is definitely uncommon. We know it from only three locations in Mount Rainier National Park, all with the same soil regime, and likely associated with the same mycorrhizal component. The plant is a partial mycoheterotroph. It does contain chlorophyll, and therefore is capable of independent photosynthesis. The role of the fungus in its life cycle is not clearly understood, but given the soil type and its associate plants, it seems likely that the fungus is acting to release some nutrient vital to C. trifida's survival. We have noted that in years when mycorrhizal activity is low due to drought or other factors, fewer of these orchids appear. Others with a wider range of mycoheterotrophic partners are less affected. Oh, for another twenty years to live, and a team of researchers at hand!

Platanthera Stricta, Slender Bog Orchid

Day 300: Mount Rainier National Park is home to at least 15 members of the Orchid family (Orchidaceae), but none has a flower larger than roughly an inch in its greatest dimension. The more floriferous members of the family put up tall spikes bearing numerous individual flowers which on close examination resemble those of corsage orchids, but on a miniature scale. Many are subtly fragrant if not particularly colourful and in fact about half are simply green or white (the exceptions are Calypso bulbosa and most Coralroots). There is some debate as to whether Orchids such as Platanthera stricta (above) can be considered truly mycoheterotrophic, but all depend on some degree of assistance from soil-borne fungi which break down nutrients into a form which can be used by the plant. Some researchers will argue that the fungus receives no reciprocal benefit from the orchid and therefore the relationship is one of parasitism, but to my way of thinking, there must be some undetected mutualism. Just because we can't quantify something doesn't mean it isn't there.

Mac Is Back!

Day 258: Mac is back! Last year, my "pet" Corallorhiza maculata was nipped off by something (deer, slug, squirrel...I don't know who the culprit was) when it was only about six inches tall. This year, she's making up for lost time by putting up two stalks which, as you can see here, are just beginning to flower. I've done my best to protect the plant by installing an 18" high chicken-wire fence around it, staked to the ground with short lengths of bamboo garden wand. That said, the Corallorhizas are amazingly resilient. Many can remain in a dormant state for years without ever breaking ground. The key lies in the plants' companion fungi. Each species of Coralroot has one or more specific "companion" fungi on which they depend. The fungi break down nutrients in the soil which can then be taken up by the plant. Currently, there is debate among botanists as to whether this is parasitism (in which case the fungus derives no benefit from the plant) or true mycoheterotrophy (a cooperative arrangement in which plant and fungus provide some requirement). I hold with the latter view on the hypothesis that if a long-term partnership has evolved, then it must in some way be advantageous to both parties. Despite the fact that we haven't identified what that exchange might be, absence of evidence does not negate the possiblility of it existing in some way we cannot detect. Good science is inquiry, not denial.

Little Mac

Day 222: Just as the buds were swelling last year, some varmint came along and nipped the top off little Mac, my "pet" Corallorhiza maculata, bringing her season to an untimely end. However, this year, she's sending up two stems, and I've put a low cage of chicken wire around her which should deter deer, if not slugs. I suspect last year's culprit was a deer or elk because the tip was cropped off about eight inches from ground level and in any event, slugs are something I don't see often in my yard (curious, that, but I won't complain). The Corallorhizas are mycoheterotrophic, i.e., they rely on a fungal partner to convert soil nutrients into a form the plant can utilize. Here, I want to add that there is again a raging debate about whether this is true mycoheterotrophy or a parasitic relationship in which the fungus gains nothing from its partner. One school of thought insists that it is parasitism, but to my way of thinking, it only looks like parasitism because we haven't figured out what the fungus is getting out of the deal. Since some Corallorhizas are very particular about which fungal partner they will accept, logic tells me that the relationship is agreeable going both ways or it would not persist. Despite our inability to determine what benefit the fungus derives, it doesn't necessarily follow that it derives nothing. That kind of closed-minded attitude in science leads down a dead-end road.

Mac Is Back!

Day 200: I've been checking every few days for the last two weeks. Mac is back! My "pet" Corallorhiza maculata in the back yard is all of an inch tall. So far, only one stem has poked through the ground, but I'm hoping for more with good reason: I believe I may have identified this particular plant's mycorrhizal associate. C. maculata is a mycoheterotroph, and as such is a bit less discriminating than some of the rarer species. It associates with a wider range of fungi, as opposed to C. trifida or C. striata which are more specific in their partnerships. My Mac may be working in tandem with Ramaria acrisiccescens, a common coral fungus which goes by the unlovely common name of "Blah Coral." Last fall, several lines of R. acrisiccescens fruited in her immediate vicinity along the shadowy edge of my wooded strip. Given the abundance of the fungus, Mac may be able to start a family of her own.

Mac Pods

Day 329: Mac pods! No, not an advertisement for Apple products, but rather the seed pods of my pet Corallorhiza maculata. If you will recall, I was lamenting the fact that I couldn't get to my beloved mycoheterotrophic plants in the spring until one day I discovered that they'd come to me in the person of Mac, who cropped up unexpectedly in my back yard. I put stakes and flagger tape around her for protection, but even so, her stem was somehow bent but not fully broken just below the inflorescence. One must take into consideration that any plant which can survive a dormancy of 25-30 years must be pretty tough. Mac refused to give up and, with the help of her mycoheterotrophic partner fungus (type unknown), withdrew sufficient nutrition from the soil to bring pods to maturity.

A lot of requirements are at play in a mycoheterotroph's life cycle. It's not enough that she makes seeds, so fine that they are referred to as "dust seeds." Despite their microscopic nature, they rely on that critical, specialized fungal component to weaken their husks before germination can occur. Not only that, but the fungus helps break down soil nutrients into a form the growing plant can use. Without that fungal partner, Mac could not grow. Her seeds could not sprout. They would lay dormant until all the stipulations of her bio-contract were again met. It goes without saying that the rarity of a particular mycoheterotroph is weighted by the range of fungal partners it will accept. Fortunately, Mac is pretty broad-minded in that regard unlike, say, Cephalanthera. Will my yard be graced by her presence again next spring? We'll just have to wait and see.

Queen Of Plants Without Chlorophyll

Day 284: About a week ago, I received an email from Arnie with the salutation, "Oh, queen of plants without chlorophyll," which was accompanied by a lovely photo of an Aphyllon species he'd found near Oregon Caves and a question about why he was seeing clumps of Castilleja at some points along the trail and Orthocarpus at others. I suggested that it might be because both plant genera are initial mycoheterotrophs (i.e., they require the assistance of a mycorrhiza to germinate), possibly even facultative mycoheterotrophs (ones which rely on a mycorrhizal "assist" even though they're capable of limited photosynthesis). Arnie likes to wind me up, and he's doing a fantastic job of it, keeping me posted almost daily on the mycoheterotrophs of southern Oregon. Damn, I wish I could take a road trip!

However, his salutation made me laugh, and also made me feel unashamedly proud of the fact that he turns to me when he has questions about mycoheterotrophic plants. In fact, it was my passion for mycoheterotrophs which inspired him to send me on a hunt for Cephalanthera austiniae, the Phantom Orchid. I think he thought it was a wild goose chase; I thought it was a snipe hunt, a way to keep me occupied and out of his hair for the rest of the season. We were both surprised when I got on the radio and announced breathlessly, "Arnie...Arnie...I'm kneeling beside two Phantoms!" as the tears streamed down my face.

That was several years ago. My botany partners and I have continued to monitor the site (the only place where Cephalanthera is known to occur in Mount Rainier National Park), and each year, we inventory Phantoms. With COVID hanging over our heads like the sword of Damocles, Joe and Sharon have gone alone twice, and last Sunday, Joe reported a census of 19 to me. This morning, I was out the door before sunrise with GPS and camera in hand. I only found 17 of Joe's specimens, but I also noted several large banana slugs in the area. I think that may be a clue into why some Phantoms disappear within a day or two and others live out their life cycle to set seed. In fact, I noted one old stalk from last year, its pods hanging dry and empty. So why is the Phantom so rare? Let's turn back to the discussion I had with Arnie: it requires a specific mycorrhizal partnership. In fact, Cephalanthera is more selective than other mycoheterotrophic species. Some combination of factors allows its existence at this site. We know that it occurs in the presence of certain other vascular plants ("plant associations"), so I believe it's possible that the mycorrhiza is dependent on something in the decaying detritus of these plant associates. Ah, so many questions! But I do know this: Cephalanthera austiniae is the true Queen of plants without chlorophyll. I am simply one of her vassals.

Heart-Leaved Twayblade, Neottia Cordata

Day 219: I was apparently absent from class the day they changed Listera to Neottia, so when I went to verify the scientific name via the Burke Herbarium's webpage, I couldn't find it under L and had to dig a little deeper to find out how the taxonomy had changed. However, phylogenetic studies revealed that the Twayblades were related to another Neottia known from northern Europe and Russia, and thus it was reassigned. While having to remember new names annoys me, it does help me understand the complex relationships in plant species around the globe.

That said, like many other Orchidaceae, the Twayblades (Neottia, Crow...Neottia) are facultative mycoheterotrophs, i.e., they contain some chlorophyll and therefore do not rely entirely on their mycorrhizal partner to extract nutrients from soil and decaying plant matter. Multiple mycorrhizal associations have been documented, including with certain jelly fungi in the Pacific Northwest, and the plants are pollinated almost exclusively by fungus gnats of various sorts. Neottia cordata is widespread in the northwestern portion of the United States, in the Great Lakes region and in Canada.

Pterospora Andromedea, Pinedrops

Day 302: Three days ago, I gave a lecture on lichens and mycoheterotrophy to a group of Park volunteers. I did not include Pinedrops in the discussion because I didn't have a suitable photo of it. We also missed it during the field trip because we took a different route; ironically, this specimen was right behind the building in which I gave my talk.

The study of mycoheterotrophic plants is still fairly new; consequently, we don't have a complete map of which fungi are associated with which plants. What we do know is that the less common the fungus is, the less common the associated plant will be. This extends backwards even further because certain fungi are only associated with specific hosts, so if the host isn't present, the fungus won't be present, and therefore the plant will not be present either. In the case of Pinedrops (Pterospora andromedea), we know that its associated fungi belong to the genus Rhizopogon, including R. arctostaphylli which utilizes Arctostaphyllos uva-ursi (common names, Bear-berry or Kinnickinnick) as its host (as a sidebar here, this is a good example of taxonomy which is actually informative, which I greatly prefer to those names which acknowledge a person, i.e., if this fungus had been called R. smithii, I'd have had to do a lot more digging to find out what its associates were). Over the last decade or so, I have observed Pinedrops less frequently than in the past, certainly far less often than I did during my early backpacking years. This would seem to indicate one of two possibile contributing factors: a decrease in the fungus species and/or a decrease in the host plant for the fungus. I have not noticed a particular decline in the Arctostaphyllos population, so theory suggests that the fungal partner's needs are not being met due to some other condition; perhaps our drier summers over the last ten years have led to its diminished presence.

I've said it before, and I hope by saying it again that I wish I had another fifty years in which to attempt to find answers. The best I can hope for is to inspire someone else to pick up the research and move it forward. Fungus seems to be at the root (literally in some cases) of much of the world's diversity. We need to further our understanding of the mycorrhizal connection to life.

Happy Sappy Family

Day 278: Pinesap (Monotropa hypopitys) is one of Mount Rainier National Park's most common mycoheterotrophic species. Even so, it's not exactly thick on the ground. As an obligate mycoheterotroph, it depends on a range of mycorrhizal species to assist with its uptake of nutrients from the soil. Newly emerging plants can be confused with even less common Gnome Plant (Hemitomes congestum). Hemitomes never develops a stalk and even at maturity, resembles the tip of a pink "pinecone" embedded in the ground. Radioactive glucose and phosphorus have both been used in field experiments to trace the relationship between Pinesap and its mycorrhizal partners (outside the Park, obviously), tests which clarified its cooperation with specific fungal species and also revealed an association with the roots of certain trees. There's a lot of activity going on in the forest underground!

A Garden Of Calypsos

Day 209: Two weeks ago, the Calypso Orchids (Calypso bulbosa) were just beginning to bud, but warmer temperatures have brought them into full flower by the hundreds in Longmire Campground. Even as brightly coloured as they are, they're easy to miss, the flowering stems standing at most four inches high and often coming up through a thick layer of moss. The flowers may measure as much as an inch and a half from the "horns" on the lower lip to the tip of the tallest petal. Partially mycoheterotrophic (also referred to as "hemi-mycoheterotrophic"), each plant has a single leaf which allows for some photosynthesis; otherwise, the nutrients necessary for Calypso's survival are broken down by soil mycorrhizae into a form this dainty native orchid can utilize.

Monotropa Uniflora, Indian Pipe

Day 290: Monotropa uniflora is one of my favourite mycoheterotrophic plants. Okay, that's a hard call to make since I'm generally fascinated by all mycoheterotrophs, but there are a few which rise straight to the top of the list. Indian Pipe is one, for all of it being fairly common in PNW forests. It is relatively non-specific in its choice of fungal partner, growing where the mycorrhizae of several different Russula species occur. Other mycoheterotrophs are more selective, although that specificity does not necessarily mean that they are more rare; the rarity depends on the fungal associate, although conversely, an abundance of the fungus does not necessarily guarantee a similar abundance of the mycoheterotrophic plant. It's kinda like that old saying from the Depression era, "If we had ham, we'd have ham and eggs, if we had eggs." Or this one: "It takes two to tango."

Mycorrhizal Associations

Day 269: While exploring a new trail in Gifford Pinchot National Forest yesterday, I came across several very dense pockets of Indian Pipe (Monotropa uniflora). After a little hunting, I found its mycoheterotrophic ally, a species of Russula. Mycoheterotrophic plants depend on a fungal component in the soil to break down nutrients into a form they can utilize. Some mycoheterotrophic species are more selective than others and may ally with only one or two fungal species while others are content to partner with an entire family of fungi. This is one factor to consider when searching for mycoheterotrophic plants: "Fyrst finde ye an fungus..."

Hemitomes Hill

Day 275: An interesting bit of information has come to light in my study of the Park's mycoheterotrophic species: the greatest variety and the largest numbers of them appear in two of only three areas having the same soil type. That's not to say they don't occur elsewhere; there are simply more of them where that soil exists. I have not yet had a chance to talk to the Park's geologist to find out what makes this soil type different, but it's something I want to research further. As for the third area, I have not explored it recently, although some fifty years ago, it was where I first observed Hemitomes congestum and my fascination with the plants then called "saprophytes" began. Of course now we know that these botanical wonders are not saprophytes at all, but mycoheterotrophs, i.e., plants which partner with a fungal component in order to fill their nutritional needs.

Our understanding of mycoheterotrophic relationships is limited. It's fairly new science, and as such, it's opened a door onto a broader scene in which fungus plays a role in the life cycles of other more mundane species as well. Some trees are known to rely on mycorrhizal connections, using the fungal web to "communicate" indicators of local stress to other trees of the same species. It's not a long reach to hypothesize that this may hold true for understory plants as well. The more I learn about mycoheterotrophy, the more convinced I am that the world goes 'round on fungus, and certain corners of it like Hemitomes Hill are richer and more diverse thanks to mycorrhizae.

Allotropa Virgata, Candystick

Day 247: Arguably the showiest of Mount Rainier National Park's mycoheterotrophic species, Allotropa virgata will make any hiker stop in their tracks for a photo. The "canes" may rise as much as 20 inches above the forest floor, and although they're usually seen as single specimens, they do form colonies. Like other obligate mycoheterotrophs, Allotropa virgata is entirely dependent on a mycorrhizal component (Tricholoma magnivelare) which facilitates the plant's uptake of nutrients from the soil. Where the fungus is absent, Candystick will not occur.

In Nature, everything holds hands, a point which becomes more obvious when you study any tightly linked relationship like mycoheterotrophy. As I learn more about these species, a question arises in my mind about the harvesting of edible wild mushrooms. Like any Hobbit worth the name, I do enjoy a meal of chanterelles, morels or boletes, and if I had been possessed of the skills necessary to make a 105% identification of Tricholoma magnivelare, I'd probably have picked the "American matsutake" as well. Fortunately, those skills are not in my repertoire, or I might have been murdering dozens or hundreds of Candysticks by my gluttony. It's a sobering thought.

Corallorhiza Maculata, Spotted Coralroot

Day 211: Following on the heels of Corallorhiza trifida, C. maculata is making an appearance in the lowland forests. Two days ago, I saw a newly emerged (unopen) specimen in a friend's woods. Yesterday, three surprised me in Pack Forest where I have never found them before.

The Corallorhizas are mycoheterotrophic species, which is to say that they lack chlorophyll and rely on the presence of specific ectomycorrhiza (fungi) which allow them to uptake nutrients from the soil. Not all of these associations have been discovered, but we do know that C. maculata is dependent on mycorrhiza of the genus Russula. The presence of Russulas in the autumn do not guarantee that an area will host Corallorhiza maculata, but if maculata is present in the spring, you can rest assured that Russulas will be evident later in the year at the same site.

There is a lesson in this, particularly for mushroom hunters: everything holds hands with something else in Nature. As strange as it may sound, over-picking of a mushroom species could lead to the extirpation or extinction of an Orchid. That's serious food for thought.