Parasitic plants with no chlorophyll
Epifagus virginiana(Beech Drops)
Sarcodes sanguinea(Snow Plant)
Allotropa virgata(Candy Stick)
Monotropa is a genus of 5 species of herbaceous perennial flowering plants, formerly classified in the family Monotropaceae, but now included within the Ericaceae. They are native to temperate regions of the Northern Hemisphere, but are generally scarce or rare.
Unlike most plants, they do not contain chlorophyll; they are myco-heterotrophs, getting their food through parasitism upon fungi rather than photosynthesis. Thus they are capable of living in very dark conditions, such as the floor of deep forests, because they do not need any sunlight.
- Monotropa hypopitys
- Monotropa uniflora
Monotropa uniflora, also known as ghost plant (or ghost pipe), Indian pipe or corpse plant, is an herbaceous perennial plant native to temperate regions of Udmurtiya in European Russia, Asia, North America and northern South America, but with large gaps between areas. It was formerly classified in the family Monotropaceae, but is now included within the Ericaceae. It is of ephemeral occurrence, depending on the right conditions (moisture after a dry period) to appear full grown within a couple of days.
Unlike most plants, it is white and does not contain chlorophyll. Instead of generating energy from sunlight, it is parasitic, more specifically a mycoheterotroph. Its hosts are certain fungi that are mycorrhizal with trees, meaning it ultimately gets its energy from photosynthetic trees. Since it is not dependent on sunlight to grow, it can grow in very dark environments as in the understory of dense forest. It is often associated with beech trees. The complex relationship that allows this plant to grow also makes propagation difficult.
The plant is sometimes completely waxy white, but often has black flecks or pale pink coloration. Rare variants may have a deep red color.
The stems reach heights of 5–30 centimetres (2.0–11.8 in), sheathed with highly reduced leaves 5–10 millimetres (0.20–0.39 in) long, best identified as scales or bracts. These structures are small, thin, and translucent; they do not have petioles but instead extend in a sheath-like manner out of the stem. As its scientific name suggests, and unlike the related Monotropa hypopitys (but like the close relation Monotropastrum humile), the stems bear a single flower 10–20 millimetres (0.39–0.79 in) long, with 3–8 translucent petals, 10–12 stamens and a single pistil. It flowers from early summer to early autumn, often a few days after rainfall. The fruit, an oval capsule-like structure, enlarges and becomes upright when the seeds mature, at this point stem and capsule looking desiccated and dark brown or black.
Like most mycoheterotrophic plants, M. uniflora associates with a small range of fungal hosts, all of them members of Russulaceae.
The plant has been used as a nervine in western herbal medicine since the late nineteenth century.
Epifagus virginiana(Beech Drops):
Epifagus virginiana — commonly called beech drops (or beech-drops, or beechdrops) — is an obligate parasitic plant which grows and subsists on the roots of American beech. It is a member of the broomrape family. Epifagus is monotypic—containing only E. virginiana. The name Epifagus derives from Greek “epi” meaning “on” or “upon”, and “Fagus” which is the genus name of beech.
Beechdrops is an annual plant native to eastern North America. It entirely lacks chlorophyll and produces many brown stems up to 30 cm tall on which it bears small white and purple flowers that appear in July through October. The flowers have tubular, zygomorphic, corollas ~8mm long containing a single style and four stamens. The dried flower stalks will persist throughout the winter. The flowers on the lower parts of the plant are cleistogamous (self-pollinating) while the tops of the stems have chasmogamous (cross-pollinating) flowers which may be sterile.
Beechdrops does contain very small alternate, scale like leaves, which are a vestigial structure from a common ancestor which was photosynthetic.
Host and symptoms
Epifagus virginiana, also known as Beechdrops, is an obligate parasite to Fagus grandifolia, Beech trees. It has been found on Maple trees but it is believed this is a case of mistaken identity. E. virginiana grows off of the roots of its host but is not known to cause significant harm to the Beech tree. Beechdrops grow on shallow roots at varying distances form the trunk of F. grandifolia. The roots of the host release a chemical that trigger the germination of E. virginiana. It is believed that the older the host tree, the more this chemical is released. The parasite develops a hastorium that grows into Beech roots to draw nutrients from its host, as Beechdrops do not photosynthesis. E. virginiana does not tolerate disturbances in its connection to F. grandifolia. As E. virginiana develops a tuber the hastorium diminishes to the point that when E. virginiana has reached maturity there is no visible hastorium, instead the parasite and host are connected through their roots and the Beechdrops’ tuber.
E. virginiana germinates when a chemical signal is released from the beech tree’s roots. During early stages of development, beechdrops live independently from its host instead relying on nutrients from the seed. It may take several years for an above ground structure to form. These early stages E. virginiana are a few millimeters in size and butter yellow. Beechdrops then develop a hastorium that grows into the host’s roots. At maturity the hastorium degrades and a tuber develops. During late summer and early fall E. virginiana flowers. Beechdrops produces two types of flowers: chasmogamous and cleistogamous. Chasmogamous flowers are cross pollinated flowers that grow at the top of the plant and are sometimes sterile. Cleistogamous flowers are self- fertile, these flowers grow at the base of the plant. Seeds from E. virginiana are small and are dispersed by rainwater. Between dispersal and germination, seeds experience a cellular change, the embryo changes colors and its cells develop granules.
E. virginiana’s host environment is mainly temperate forests in the Midwest of the U.S. Beechdrops are found in Indiana, Ohio, and Michigan in significant numbers. They have been documented along the East Coast from Maine to South Carolina. In these environments E. virginiana are pollinated by P. imparis, the winter ant. This insect pollination is required for pollination in the chasmogamous flowers. E. virginiana relies upon ant pollination to produce cross pollinated seeds along with self-fertilized seed. It is not believed that ants pollinate the self-fertile cleistogamous flowers. Beechdrops are used to monitor forest health because of their dependence on their host and the sensitivity to its environment. E. virginiana’s host, Beech trees, can advance in a forest faster than E. virginiana is able to. The presence of F. grandifolia is used to predict when E. virginiana will arrive in an area. E. virginiana is not a tree health concern but the lack of its presence is a sign that forest health is declining.
Sarcodes sanguinea(Snow Plant):
Sarcodes is the monotypic genus of a north-west American flowering springtime plant in the heath family (Ericaceae), containing the single species Sarcodes sanguinea, commonly called the snow plant or snow flower. It is a parasitic plant that derives sustenance and nutrients from mycorrhizal fungi that attach to roots of trees. Lacking chlorophyll, it is unable to photosynthesize. Ectomycorrhizal (EM) symbioses involve a mutualism between a plant root and a fungus; the plant provides fixed carbon to the fungus and in return, the fungus provides mineral nutrients, water and protection from pathogens to the plant. The snow plant takes advantage of this mutualism by tapping into the network and stealing sugars from the photosynthetic partner by way of the fungus. This form of parasitism is known as mycoheterotrophy.
There is a group of non-green flowering plants that is related to the heaths (blueberries, cranberries, rhododendrons) and is often included in the heath family (Ericaceae). This group of non-green plants is a subset of the heath family. Let’s call them the monotropoids. Are they parasites? Yes, but in an unusual way. The monotropoids were thought to be “saprophytes.” A saprophyte lives on dead plant or animal material, but the monotropoids don’t do that. They are parasites on fungi, we can call them mycoparasites. But they don’t kill the fungi. The fungi infect the short, stubby roots of the monotropoids, and transfer food and water into the roots. The fungi live in the dense litter of dead leaves in wet forests.
The most striking of the monotropoids is the snow plant, Sarcodes sanguinea. Sarcodeswas called the snow plant because it was thought to come up through the snow. But it really doesn’t–it comes up after the snow melts or has mostly melted. It grows in conifer forests of California, and portions of western Nevada and northern Baja California.
Some plants of Sarcodes are brilliant red, others are more nearly rose-colored. Why the bright color? Nobody really knows. Such a bright color might attract pollinating insects in the rather shady forest floor areas where the snow plant grows. The flowers point downward. This plant has already formed some young fruits, lower on the stalk, although the youngest flowers, at the top of the stem, are still opening.
The underground portions of the snow plant are white. In this picture, you can see the tight cluster of short, knobby roots. The roots contain fungi which extend into the conifer forest leaf litter in which Sarcodes grows. The snow plant is fed water and nutrients from the fungi. These fungi also extend into the roots of pines and other conifers. Using radioactive carbon, one study showed that the sugars from the conifer roots enter the fungi and then are transferred into the roots of the snow plant. The flowers of Sarcodes point outward for a short time, then point downward. They open in a narrow tube. In front of this flower is one of the leaves of the snow plant. And we have the view looking into some open flowers of Sarcodes, the snow plant.
The inside of a snow plant flower. When the flower is cut open, the large white ovary, which will contain seeds when it mature, appears. The stamens, tan-color, contain pollen; and the sticky bright red surfaces of the stigma, which collects pollen, can easily be seen. A flower of the snow plant, cut open, reveals the stamens (yellow-brown) just opening to release pollen. The stamens of this flower have finished shedding their pollen. The pollen escapes through the holes in the tips of the stamens. Does this flower look upside down? Remember, the flowers of the snow plant point downwards once they open. Stamens that open by holes instead of slits are often thought to release pollen when they shake. The vibrations of a visiting insect may cause such shaking.
Part of a snow plant, Sarcodes, showing fruits developing. The fruits are colorful and fleshy at this stage, and might think that some fruit-eating animal might be attracted to them. However, when they are mature, the fruits of the snow plant are dry and shed fruits through slits in the fruit wall. A cross-section of a developing fruit of the snow plant. The seeds are already brown, their color at maturity. The center of the fruit, however, is still white and fleshy. Seeds of the snow plant, greatly enlarged. They have rough surfaces. Nobody knows how they are dispersed from one place to another. In order to grow, they must become buried in the leaf litter of a conifer forest. Probably they need to contact particular fungi in order to germinate. The geographical range of the snow plant is probably limited by the extent of the conifers and the fungi that the snow plant depends upon.
Conopholis americana (Squawroot):
Conopholis americana (American cancer-root or squawroot or bumeh or bear corn) is a perennial, non-photosynthesizing (or “achlorophyllous”) parasitic plant, from the family Orobanchaceae and more recently from the genus Conopholis but also listed as Orobanche, native but not endemic to North America and when blooming, resembles a pine cone or cob of corn growing from the roots of mostly oak and beech trees.
Conopholis americana is parasitic on the roots of woody plants, especially oaks (genus Quercus) and beech (genus Fagus). The only part of the plant generally seen is the cone-shaped inflorescence, which appears above ground in spring. The entire structure is a yellowish color, turning to brown and achieves heights of 10 centimeters (4 in) to 20 centimeters (8 in) tall.
Stems and leaves
Stout and unbranched 1.3 centimeters (0.5 in) to 2.5 centimeters (1 in) thick stems. Since C. americana does not photosynthesize it also does not have true leaves; it has instead simple, ovate, tiny scales 1.3 centimeters (0.5 in) long and brown, which appear underneath each flower.
Conopholis americana produces spikes of yellow to cream flowers densely crowded all around the stem. Each flower is 5-parted, 8 millimeters (0.3 in) to 13 millimeters (0.5 in) long, tubular with a swollen base and facing downwards. As the flowering spike matures and begins to wither and becomes brown throughout the summer and often persisting through the winter, by which time it has become shriveled and black. There is no noticeable floral scent.
Fruits and reproduction
Each flower is replaced by a seed capsule that is longer than it is wide and contains many small seeds. This plant spreads to new locations by reseeding itself.
The root system is parasitic on the roots of oak trees (Quercus spp.); dependent on the host tree for its nourishment, the suckers of the parasitic roots cause the formation of large rounded knobs on the roots of the host tree.
Found growing on roots in wooded ravines in every state of the United States east of the Mississippi River.
- Eastern Canada: Nova Scotia, Ontario, Quebec
- Northeastern U.S.A.: Connecticut, Indiana, Maine, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, West Virginia
- North-Central U.S.A.: Illinois, Wisconsin
- Southeastern U.S.A.: Alabama, Delaware, Florida, Georgia, Kentucky, Maryland, North Carolina, South Carolina, Tennessee, Virginia
It is considered an exploitably vulnerable species in New York, a threatened species in New Hampshire and a special concern in Rhode Island.
A similar species Pleuricospora fimbriolata:
Pleuricospora is a monotypic genus of flowering plants in the heath family containing the single species Pleuricospora fimbriolata, which is known by the common name fringed pinesap. It is native to the forests of the west coast of North America from British Columbia to the San Francisco Bay Area. This perennial herb is a mycoheterotroph, parasitizing fungi for nutrients. It is yellowish, cream or white in color, lacking chlorophyll, with the tips of the bracts darkening with age. It produces a fleshy stemless peduncle above the leaf litter of the forest floor, reaching no more than 10 to 12 centimeters tall. Leaves are reduced to scales or absent, as the plant does not perform photosynthesis. The aboveground portion of the plant is essentially just inflorescence, with cylindrical whitish flowers blooming for a short time. The flower has four or five petals and about eight stamens in its throat. It produces a fleshy berry under a centimeter wide containing many tiny, sticky seeds. The seeds are dispersed when small mammals eat the fruits.
Pterospora andromedea (Pinedrops):
Pterospora, commonly known as pinedrops, woodland pinedrops, Albany beechdrops, or giant bird’s nest is a North American genus in the subfamily Monotropoidiae of the heath family, and includes only the species Pterospora andromedea. It grows in coniferous or mixed forests. It is widespread across much of Canada as well as the western and northeastern United States to and northern Mexico. Along with Monotropa it is one of the more frequently encountered members of the Monotropoidiae.
The genus name is derived from the morphology of the seeds which have narrow flaps of tissue on the side and therefore appear winged: pteron (Gr.) = winge, spora (Gr.) = seed. The specific name andromedea derives from the resemblance of the flowers to those of another genus in the Ericaceae, Andromeda.
The visible portion of Pterospora andromedea is a fleshy, unbranched, reddish to yellowish flower spike (raceme) 30–100 cm (12–39.5 in) in height, though it has been reported to occasionally attain a height of 2 meters (6.6 feet). The above-ground stalks (inflorescences) are usually found in small clusters between June and August. The inflorescences are hairy and noticeably sticky to the touch. This is caused by the presence of hairs which exude a sticky substance (glandular hairs). The inflorescences are covered by scale-like structures known as bracts. The upper portion of the inflorescence has a series of yellowish, urn-shaped flowers that face downward. The fruit is a capsule.
Like all members of the Monotriopoidiae (see Monotropa), Pterospora andromedea lacks chlorophyll (trace amounts have been identified, but not enough to provide energy for the plant or to color it). Plants exist for most of their life as a mass of brittle, but fleshy, roots. They live in a parasitic relationship with mycorrhizal fungi, in which plants derive all their carbon from their associated fungus, but the relationship is not yet well understood. The term for this kind of symbiosis is mycoheterotrophy. In Pterospora the association is with a very limited number of fungi in the genus Rhizopogon, including Rhizopogon subcaerulescens, R. arctostaphyli, and R. salebrosus. A note of caution: unlike plants, fungi are not yet well categorized and so species’ names are likely to change frequently as more research is done and Rhizopogon is particularly hard to taxonomically categorize. Pterospora has yet to be discovered with any species outside the genus Rhizopogon.
Pterospora has consistently been shown to be more closely related to Sarcodes than any other member of the Monotropoidiae.
A similar looking flowering plant Striped Coral Root (Corallorhiza striata) is actually an orchid:
Allotropa virgata (Candy Stick):
Allotropa virgata is in the family Ericaceae (Heath Family) and is the only species of the genus Allotropa. It is a perennial plant that gets its common names from the distinct white and red or maroon stripes along its erect peduncle. A. virgata are non-green as they lack chlorophyll, instead obtaining nutrition from neighboring green plants through a fungal intermediate. Allotropa virgata feeds exclusively on Matsutake mushroom mycelium:
Its common names include Sugarstick, Sugar-stick, Candy-striped allotropa and Barber’s Pole.
Allotropa virgata is found in the oak, coniferous and hardwood forests of the Pacific Northwest. It grows from 75 to 3000 meters in elevation in the High Sierra Nevada, High Cascade Range and up through British Columbia. There is also suitable habitat in Idaho and Montana.
A. virgata has an underground stem (rhizome) with brittle roots. The scale-like leaves are along the striped peduncle with a raceme-like inflorescence. The peduncle is persistent after the seeds have been dispersed and tends to turn brown. The bracts of the inflorescence are less than 3 cm and the pedicels are not recurved.
The individual flowers generally don’t have sepals but if they do, have 2 to 4. Often the petals of the flower are incorrectly considered sepals. The corolla has 5 white petals in a cup shape, all petals are free and concave. From the corolla there are 10 protruding stamens, maroon in color, with dehiscent anthers. The superior ovary has 5 chambers with a style under 2 mm and a disk-like stigma. The short nectary is disk-like as well with 10 lobes.
The fruit of A. virgata are capsules which dehisce lengthwise through the ovary wall near the center of each of the 5 chambers. This dehiscence allows the many fusiform seeds from each chamber to be dispersed.
Allotropa is derived from Greek and means ‘different nourishment’ (allo– ‘different’, ‘other’; tropus– ‘nourishment’).
The plant is grown in the Taklamakan desert, and is traditionally used for medicines and foods in China.
A recent study found a combination of Cistanche Tubulosa and Laminaria Japonica Extracts to be “promising substances for promoting health of the scalp and hair treatment”
The main sources of the Chinese herbal medicine cistanche (Chinese: 肉苁蓉, pinyin ròucongróng) are Cistanche salsa and Cistanche deserticola, although it may also be obtained from C. tubulosa. The drug, known in Chinese as suosuo dayun, is collected in spring before sprouting, by slicing the stems of the plant.
Recent Chinese studies demonstrated that C. tubulosa contains several phenylethanoid glycosides, e.g. echinacoside, acteoside, and iso acteoside, which potentially can be used as regulators of blood glucose level for treatment of Type I and Type II diabetes mellitus.
Cistanche Salsa is strikingly purple: