Notable Monotropes: Snow Plants & Pinedrops
A week or two ago, while hiking in the Wawona area of Yosemite National Park (taking in the glorious fall colors and hoping beyond hope to see a Great Gray Owl), I came across a dried up stalk of Woodland Pinedrops (Pterospora andromedea) growing on the forest floor. I'm sure most people would have walked right on by, but of course I was thrilled! I stopped to take a bunch of photos (Eric wondered, I'm sure, what all the fuss was about over something so seemingly unspectacular) and once home, decided it was time to introduce you to a few of California's magnificent monotropes!
Pinedrops are a lesser-known cousin of the showy Snow Plant (Sarcodes sanguinea), both of which are included in the heath family, Ericaceae. Other plants in this family include California's 40+ manzanita species, John Muir's beloved Cassiope, the abundant Salal of the Pacific Northwest, and common favorites like rhododendrons, blueberries and huckleberries (plants with urn-shaped flowers). But Snow Plants and Pinedrops are also considered members of the Indian-pipe subfamily, Monotropaceae, a group of mycoheterotrophs or mycoparasites, plants that obtain nutrients by parasitizing fungi.
Snow Plants have long been misclassified as saprophytes.
(And here we must stop to define saprophytes! A saprophyte is an organism - a plant, fungus or microorganism - that lives on dead and decaying organic matter. Ecologically, they are heterotrophs (consumers, like animals) rather than autotrophs (producers, like other plants) within the food web. Fungi like the familiar and humble mushroom are common examples of saprophytic organisms.)
Since Snow Plants and their kin lack chlorophyll and are therefore incapable of manufacturing their own sugars, they were once thought to belong to this group of saprophytes, living on dead organic matter. But that turns out not to be entirely correct.
Snow Plants and Pinedrops, as well as other monotropes, may also be considered parasitic on the roots of the pine trees they are so commonly associated with, but that isn't quite the whole story either.
To really get down to specifics, we must first understand the symbiotic relationship that exists between conifers and underground mycorrhizal fungi. Then we can begin to understand that Snow Plants are actually parasites on this fungi, rather than on tree roots, obtaining nutrients from the mycorrhizae. They are, in fact, mycoparasitic, a term meaning parasitic on fungi.
Mycorrhizae (a word which literally translates to "fungus-roots") are an essential part of the forest ecosystem, and many conifers (as well as other plants) depend on these fungi to live healthy lives. Strands of cells called mycelia make up the mycorrhizae, growing in a web throughout the soil and root systems of forest plants. Mycelia effectively become extensions of plants' root systems, enabling them to take in water and nutrients more efficiently. The relationship is mutually beneficial, as the trees provide the fungi with energy (the products of the trees' photosynthesis, known as photosynthate) and the fungi provide the trees with a more efficient system of nutrient uptake.
Snow Plants essentially steal some of this energy, or photosynthate, from the mycorrhizae, which had obtained it fairly from the trees by means of the aforementioned agreed upon exchange of goods and services. Monotropes are then, essentially, fascinating little freeloaders.
Though it may not look like it at first glance, the Snow Plant in bloom really is covered in little downward-pointing flowers and produces seeds when pollinated, just like other angiosperms. It is considered an "herbaceous perennial wildflower," though alien-like fungi-creature might initially seem more appropriate!
The Snow Plant is not common, and belongs almost exclusively to California; some are found in Nevada and Oregon as well. It grows up to 20 inches tall, and is found singly or in clusters on the floor of coniferous forests. They thrive in the thick humus of the montane region from 4,000 to 8,000 feet in elevation. Typically Snow Plants are in bloom from April or May to July, sometimes poking brave scarlet heads up through melting snow. When you meet the Snow Plant, you are unlikely to mistake it for anything else!
Woodland Pinedrops are also covered in tiny flowers when in bloom, which generally happens during the late summer, though they seem to be particular little plants and cannot be depended on to come up every year. Pinedrops are fairly uncommon, though their range covers much more of the United States than the Snow Plant. Habitat preferences are similar to that of the Snow Plant and other monotropes, found growing on dark forest floors in association with conifers such as Ponderosa Pine and Douglas Fir.
California is home to a few other notable monotropes as well: Pinesap (Monotropa hypopitys) and Indian Pipe (Monotropa uniflora), both of Northern California; Sugar Stick (Allotropa virgata), Fringed Pinesap (Pleuricospora fimbriolata) and rare California Pinefoot (Pityopus californicus) of montane forests; and the redwood forests' own Gnome Plant (Hemitomes congestum).
So, while birds and boughs beckon your gaze upward, next time you are strolling through the evergreens pay some attention to the dark forest floor as well and see what interesting plants may await your discovery there!
 |
| Dried stalk of Pinedrops - unassumingly beautiful! |
Pinedrops are a lesser-known cousin of the showy Snow Plant (Sarcodes sanguinea), both of which are included in the heath family, Ericaceae. Other plants in this family include California's 40+ manzanita species, John Muir's beloved Cassiope, the abundant Salal of the Pacific Northwest, and common favorites like rhododendrons, blueberries and huckleberries (plants with urn-shaped flowers). But Snow Plants and Pinedrops are also considered members of the Indian-pipe subfamily, Monotropaceae, a group of mycoheterotrophs or mycoparasites, plants that obtain nutrients by parasitizing fungi.
Snow Plants have long been misclassified as saprophytes.
(And here we must stop to define saprophytes! A saprophyte is an organism - a plant, fungus or microorganism - that lives on dead and decaying organic matter. Ecologically, they are heterotrophs (consumers, like animals) rather than autotrophs (producers, like other plants) within the food web. Fungi like the familiar and humble mushroom are common examples of saprophytic organisms.)
Since Snow Plants and their kin lack chlorophyll and are therefore incapable of manufacturing their own sugars, they were once thought to belong to this group of saprophytes, living on dead organic matter. But that turns out not to be entirely correct.
 |
| Snow Plant growing in forest humus at the foot of a pine |
Snow Plants and Pinedrops, as well as other monotropes, may also be considered parasitic on the roots of the pine trees they are so commonly associated with, but that isn't quite the whole story either.
To really get down to specifics, we must first understand the symbiotic relationship that exists between conifers and underground mycorrhizal fungi. Then we can begin to understand that Snow Plants are actually parasites on this fungi, rather than on tree roots, obtaining nutrients from the mycorrhizae. They are, in fact, mycoparasitic, a term meaning parasitic on fungi.
Mycorrhizae (a word which literally translates to "fungus-roots") are an essential part of the forest ecosystem, and many conifers (as well as other plants) depend on these fungi to live healthy lives. Strands of cells called mycelia make up the mycorrhizae, growing in a web throughout the soil and root systems of forest plants. Mycelia effectively become extensions of plants' root systems, enabling them to take in water and nutrients more efficiently. The relationship is mutually beneficial, as the trees provide the fungi with energy (the products of the trees' photosynthesis, known as photosynthate) and the fungi provide the trees with a more efficient system of nutrient uptake.
Snow Plants essentially steal some of this energy, or photosynthate, from the mycorrhizae, which had obtained it fairly from the trees by means of the aforementioned agreed upon exchange of goods and services. Monotropes are then, essentially, fascinating little freeloaders.
 |
| Summer flowers of the Snow Plant |
Though it may not look like it at first glance, the Snow Plant in bloom really is covered in little downward-pointing flowers and produces seeds when pollinated, just like other angiosperms. It is considered an "herbaceous perennial wildflower," though alien-like fungi-creature might initially seem more appropriate!
The Snow Plant is not common, and belongs almost exclusively to California; some are found in Nevada and Oregon as well. It grows up to 20 inches tall, and is found singly or in clusters on the floor of coniferous forests. They thrive in the thick humus of the montane region from 4,000 to 8,000 feet in elevation. Typically Snow Plants are in bloom from April or May to July, sometimes poking brave scarlet heads up through melting snow. When you meet the Snow Plant, you are unlikely to mistake it for anything else!
 |
| November seed capsules of Pinedrops |
Woodland Pinedrops are also covered in tiny flowers when in bloom, which generally happens during the late summer, though they seem to be particular little plants and cannot be depended on to come up every year. Pinedrops are fairly uncommon, though their range covers much more of the United States than the Snow Plant. Habitat preferences are similar to that of the Snow Plant and other monotropes, found growing on dark forest floors in association with conifers such as Ponderosa Pine and Douglas Fir.
California is home to a few other notable monotropes as well: Pinesap (Monotropa hypopitys) and Indian Pipe (Monotropa uniflora), both of Northern California; Sugar Stick (Allotropa virgata), Fringed Pinesap (Pleuricospora fimbriolata) and rare California Pinefoot (Pityopus californicus) of montane forests; and the redwood forests' own Gnome Plant (Hemitomes congestum).
So, while birds and boughs beckon your gaze upward, next time you are strolling through the evergreens pay some attention to the dark forest floor as well and see what interesting plants may await your discovery there!
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