Bob's Brain on Botany -- Winter, 2010

Common Evergreen Conifers
Part 1: Pinaceae, the Pine Family

When most people think of conifers, they think of pine (genus Pinus in the family Pinaceae), although a spruce or fir is very likely to be called a "pine tree" by somebody not yet familar with the fine points of plant identification. Pines are needle-leaved evergreens, the leaves of which, except those of a Great Basin species aptly named Pinus monophylla, are bundled together in sheathed fascicles of 2-5. There are only four native pines in Ohio: shortleaf (P. echinata), pitch (P. rigida), white (P. strobus), and Virginia pine (Pinus virginiana, also known as "scrub pine").

Here along Rte 36/37 in Delaware County there are scattered rows of planted Virginia pines.

Roadside Virginia pines. February 26, 2010. Delaware, Ohio.

Virginia pine seed cone scales are distinctively spine-tipped. The leaves are short, and bundled in twos.

Virginia pine branch. February 18, 2010. Delaware County, Ohio.

Closeup, it is evident that the fascicled leaves are enveloped at their bases by a papery sheath.

Virginia pine leaves are fascicled in pairs.

Ohio isn't rich in native conifers. Two northern genera in the Pinaceae that make it to nearby West Virginia --Picea (spruce) and Abies (fir) --are absent even though we have bogs in northeast OH and moderately high-altitude acid-soil areas in southern OH where it seems they could occur. Alas, they don't. Nonetheless, various European and western North American spruces are very abundant as lawn, park, and roadside ornamentals. Here's some kind of spruce at Greenlawn Cemetery in Columbus.

Ornamental spruce tree at Greenlawn Cemetery. Columbus, Ohio. February 22, 2010.

Spruces bear their leaves singly. The cones are pendant.

Branches of ornamental spruce tree at Greenlawn Cemetery, Columbus, Ohio. February 22, 2010.

The leaves of spruces are 4-sided, spreading off the twig in all directions. Their bases are attached to, and lie alongside, the twigs, giving them a very rough appearance. The leaves are quite sharp (ouch!) and smell somewhat cat pee-ey.

Spruce leaves are singly attached and the persitent bases give the twigs a rough appearance.

Another needle-leaved conifer, leaves attached singly, is fir (genus Abies). Here is some type of fir growing as an ornamental on the OSU campus.

A fir tree on the OSU Columbus campus. February 19, 2010.

Fir leaves are attached singly. Compared to those of spruce, fir leaves are soft, flat, blunt, and sweet smelling. That pleasant "pine-needle" sachet from the souvenir shop is probably a fir-neeedle sachet.

Branch of ornamental fir on the OSU campus. February 19, 2010.

Fir twigs, in contrast to those of spruce, are smooth. Fir leaf bases are expanded, looking like little suction cups.

Fir twig.

Eastern hemlock, Tsuga canadensis, is a native Ohio member of the Pinaceae that is locally abundant in cool ravines in unglaciated southern portions of the state. It's also a beautiful lawn ornamental. Here's one in the Clintonville neighborhood of Columbus.

Eastern hemlock tree. February 15, 2010. Columbus, Ohio.

Eastern hemlock leaves are flattened, and attached singly. The seed cone are small. They ripen in autumn and release their seeds during autumn and winter.

Eastern hemlock. February 15, 2010. Columbus, Ohio.

Eastern hemlock leaves are spirally arranged around the twig, but the upper and lower ones are splayed sideways, resulting in flattened sprays of foliage. Prominent paried white lines of stomates (breathing pores) mark the underside of each leaf. Like those of spruce, eastern hemlock twigs have a rough appearance owing to persistent leaf bases lying alongside the twigs.

Eastern hemlock twig.

The remaining evergreen member of the Pinaceae is not an Ohio native. This is Douglas-fir, Pseudotsuga menzeisii, the massive tree, overtopped only by the redwoods, that dominates conifer forests of the Pacific northwest and Rocky Mountains. The species is planted sparingly in parks and cemeteries. Here's one at Greenlawn, pretty wimpy, but Douglas-fir nonetheless.

Douglas-fir at Greenlawn Cemetery. February 22, 2010.

Eerily similar both to spruce (Picea) and fir (Abies), and with a genus name meaning "false hemlock," Douglas-fir can indeed be a fooler. Fortunately, a merciful natural selecter installed an easy identification module: seed cones that are most distinctive. Doug-fir cones have very long appendages (bracts) extending out above each of the woody seed-bearing scales. In other conifers, these bracts are so short as to be out of sight, obscured by the scales. Pseudotsuga cone bracts bear a whimsical resemblance to mice crawling into the cones, with only their back legs and tail protruding.

Douglas-fir at Greenlawn Cemetery. February 22, 2010.

Douglas-fir leaves are attached singly and spirally inserted, thus the tree looks much like spruce or fir. The texture of the twigs is intermediate between the roughness of spruce and the smoothness of fir.

Douglas-fir leaves are singly attached, and spirally inserted on twigs that are a bit rough.

Part 2: Cupressaceae, the Cypress family

Members of the Cupressaceae bear small needle like or, more often, scale-like leaves that are opposite or whorled, crowded and often overlapping. Of the three northeastern U.S. genera, two occur naturally in Ohio: Thuja (northern whitecedar) and Juniperus (juniper). Missing is a species of Chamaecyparis, C. thyoides, Atlantic whitecedar, that occurs on the coastal plain. Atlantic whitecedar (spelled as one word because its really a cypress, not a cedar) and other species in the genus are cultivated ornamentals, so there must be some Chamaecyparis lurking about in Columbus but my efforts to track one down for this article have failed.

Northern whitecedar (deliberately spelled as one word because it's really a cypress, not a cedar), found naturally in both wet fens and on dry limestone outcrops, is also a widely planted ornamental. Below, see planted whitecedars forming a semicircular backdrop of a little amphitheater on the OSU campus. (Note also the tallest tree in the backgound, a deciduous conifer, baldcypress (Taxodium distichum, family Taxodiaceae.)

Northern whitecedar at OSU, Columbus, Ohio. February 7, 2010.

Thuja produces little upright seed cones that are oblong, with overlapping scales.

Northern whitecedar. February 7, 2010.

The leaves of Thuja are "decussate," meaning that they are arranged leaves in opposite pairs that are perpendicular to one another. A further distinction is that the upper and lower leaves are flat, but the lateral ones are folded over, clasping the upper and lower ones. It reminds me of someone holding a big hamburger with both hands.

Northern whitecedar leaves are scale-like and in overlapping pairs.

Juniper, Juniperus virginiana, also called eastern redcedar (deliberately spelled as one word because it's really a cypress, not a cedar) is an extremely common and abundant conifer, especially in areas with calcareous soil. It has a distinctively dark pyrimidal form, commonly seen scattered in old fields, where it is a pioneer in secondary succession.

Eastern redcedar. Marion, Ohio. February 15, 2010.

Unlike most other conifers, which are monoecious, junipers are dioecious, i.e., having separate male and female individuals. The females bear highly modified cones that, having fleshy and fused scales, look quite berry-like. The "berries" of J. communis (common juniper, a shrubby species that occurs in Ohio, but is actually not very common) constitute the principal flavoring used in making gin. The word "gin" is derived from a modification of a French or Dutch word for "juniper." They are an important winter food source for many songbirds, including cedar waxwings.

Female redcedar bearing berry-like seed cones, February 15, 2010.

Eastern redcedar displays considerable variability in its foliage, often with both types on the same tree. The tiny scale-like leaves may either spread out from the twigs, or instead lay appressed against the twigs in the manner of Thuja. Here's a spreading-leaved sample.

Eastern redcedar twig showing spreading-leaved form.

...and here's an appressed one.

Eastern redcedar twig showing appressed-leaved form.

Part 3: Taxaceae, the Yew Family.

One local evergreen conifer doesn't produce cones. Taxus (yew, in the family Taxaceae) seeds are instead borne singly and look very berry-like, as they are provided with a fleshy covering at maturity. The fleshy part, a highly modified seed cone scale, is the only part of the plant that is non-toxic. Here's what a yew seed looked like in mid-summer several years ago. This is one of several very commonly planted ornamental Taxus species, perhaps English yew (T. baccata) or some Asian species. The native yew, T. canadensis, is an uncommon shrub in the understory of rich deciduous and mixed deciduous-conifer woods, occuring mainly in the northeastern portion of the state. Yew is indeed a gymnosperm (i.e., "naked-seeded") plant. Note that the seed is not enclosed by this fruity-looking structure; it is merely surrounded by it.

Midsummer yew seed. July 31, 2005. Columbus, Ohio.

Currently, the yew shrub seems a little more concerned with survival than reproduction.

Yew shrub. February 15, 2010. Columbus. Ohio.

The Playboy Mansion is being redecorated. The interior designer decided it would be nice to employ paint colors exactly matching those found on Mr. Hefner's favorite plant, if only it could be determined what that plant was. The designer, as luck would have it, was a pretty woman who decided to ask "Hef" for the name of his favorite plant. Expecting professionalism even from a well-known "womanizer," she was taken aback when he said "I love yew." Consequently she went to the gardener to find out what plant to sample the colors from, for the paint formulation. The gardener's advice was simple: "Use Hugh's yew's hues."

Yew leaves are flat, and arranged in flat sprays much like eastern hemlock.

Yew shrub. February 15, 2010. Columbus Ohio.

Closeup, beneath, note that yew leaves bear two broad bands of stomates. The overall color is uniform, not white-striped as eastern hemlock.

Yew leaves are uniformly colored beneath.

Midwinter Fungi
Jan.-Feb., 2010

Perhaps the most magnificant thing that nature ever selected, the "shotgun fungus," Pilobolus grows on the dung of grass-grazing mammals, including horses, cows and sheep. It's a member of the group of fungi called "zygomycetes" (Class Zygomycota). Zygomycetes are distinguished by having a coenocytic (multinucleate) mycelium (the threads that comprise the body of a fungus) from which extend upward, either as a result of a sexual or an asexual process, elongate swollen-tipped stalks, each topped by a case of spores, a sporangium.

To experience Pilobolus, simply ask a farmer for a few dollops of sheep (or horse, or cow) poop. It helps if you provide her/him a container, such as a lettuce crisper, or a piece of "Tupperware." Let the poo sit, covered so that it stays moist, for a few days, then lift the lid and behold such extreme wonderfulness that redwoods, pandas and whales will hang their heads dejectedly upon the sudden realization that they are so enormously out-classed.

Pilobolus adorns ovine dropping brought in from the barn. February 2, 2010.

Pilobolus is neatly adapted for moving from one dung-patty to another. The swollen top of the sporangium-producing stalk (sporangiophore) is transparent and functions as a lens, enabling the sporangiophore to position itself at a low angle by pointing towards the rising sun. In this way the spores (packed together into the dark compressed "hat" at the very top of the stalk) are dispersed away from their home dung-pile when they are expelled ballistically as much as 6 feet away. This is necessary because grazing herbivores avoid dung as they merrily munch the nearby grass. While they munch the grass they also munch Pilobolus spores, and a new generation of fungus finds itself in just the right place to colinize (and help recycle) a new patch of dung.

Pilobolus, the hat-tossing" fungus, orients towards the rising sun and shoots spores away from home.

Another major group of fungi are the basidiomycetes, sometimes called "club fungi," in the Class Basidiomycota. This group includes mushrooms, one species of which is quite tiny, and grows from crevices in the bark of a sweetgum tree in front of my house. Photographing the mushroom is much more interesting than shoveling snow. I think this is Mycena corticola.

The tiny "bark mycena" (Mycena corticola) mushroom, Orthotrichum pumilum moss
and Candelaria concolor lichen growing on an urban sweetgum tree. February 6, 2010. Columbus, Ohio.

Lichens are well known symbiotic dual organisms --an alga and a fungus. But they're really mostly fungus, and often display the characteristic fungal spore-producing structures --usually ascocarps --of their group, usually the sac fungi (Class Ascomycota). Here's Physcia millegrana growing on the bark of an American sycamore tree alongside the Scioto River in Columbus, Ohio. This is a narrow-lobed light gray foliose lichen that has fluffy-looking edges owing to its abundant marginal soredia --powdery granules containing both fungal hyphae and alga cells that break away from the lichen, enabling dispersal and reproduction. Note also the cup-shaped apothecia --fungal reproductive structures lined with microscopic spore-producing sacs (asci). Growing with the gray Physcia is a very common associate found even on roadside trees in urban areas, the bright yellow Candelara concolor.

Physcia millegrana.

Here's a little more Candelaria concolor, along with Tortula papillosa (family Pottiaceae) moss and a sycamore lace bug insect.

Moss, bug and lichen. January 21, 2010. Columbus, Ohio.

On a rock in a wooded area alongside the Scioto River, some quite small lichens are growing. One of these is a grayish-brown foliose one with narrow lobes. It's Phaeophyscia adiastola, mingling with Candelaria.

Foliose lichens on rock.

A couple other small lichens are "crustose" one. i.e., species lacking a lower layer (cortex) and that are so tightly adherent to the substrate that it is nearly imposssible to separate the lichen from it. This one, Caloplaca sideritis, bears abundant apothecia (cup-shaped ascocarps).

The crustose lichen Caloplaca sideritis on rock.

Another crustose lichen sharing rocky real estate with Caloplaca is even less conspicuous because its ascocarps are of a type called "perithecia," that are flask-shaped and sunken deep within the tissues of the lichen. All that are visible are the perithecia necks, seen as scattered black spots on the surface of the lichen, Endocarpon pallidum. Note also an Orthotrichum moss, and a bit more of the foliose Phaeophyscia.

The crustose lichen Endocarpon pallidum.


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	Common Evergreen Conifers Part 1: Pinaceae, the Pine Family When most people think of conifers, they think of pine (genus Pinus in the family Pinaceae), although a spruce or fir is very likely to be called a "pine tree" by somebody not yet familar with the fine points of plant identification. Pines are needle-leaved evergreens, the leaves of which, except those of a Great Basin species aptly named Pinus monophylla, are bundled together in sheathed fascicles of 2-5. There are only four native pines in Ohio: shortleaf (P. echinata), pitch (P. rigida), white (P. strobus), and Virginia pine (Pinus virginiana, also known as "scrub pine"). Here along Rte 36/37 in Delaware County there are scattered rows of planted Virginia pines. Roadside Virginia pines. February 26, 2010. Delaware, Ohio. Virginia pine seed cone scales are distinctively spine-tipped. The leaves are short, and bundled in twos. Virginia pine branch. February 18, 2010. Delaware County, Ohio. Closeup, it is evident that the fascicled leaves are enveloped at their bases by a papery sheath. Virginia pine leaves are fascicled in pairs. Ohio isn't rich in native conifers. Two northern genera in the Pinaceae that make it to nearby West Virginia --Picea (spruce) and Abies (fir) --are absent even though we have bogs in northeast OH and moderately high-altitude acid-soil areas in southern OH where it seems they could occur. Alas, they don't. Nonetheless, various European and western North American spruces are very abundant as lawn, park, and roadside ornamentals. Here's some kind of spruce at Greenlawn Cemetery in Columbus. Ornamental spruce tree at Greenlawn Cemetery. Columbus, Ohio. February 22, 2010. Spruces bear their leaves singly. The cones are pendant. Branches of ornamental spruce tree at Greenlawn Cemetery, Columbus, Ohio. February 22, 2010. The leaves of spruces are 4-sided, spreading off the twig in all directions. Their bases are attached to, and lie alongside, the twigs, giving them a very rough appearance. The leaves are quite sharp (ouch!) and smell somewhat cat pee-ey. Spruce leaves are singly attached and the persitent bases give the twigs a rough appearance. Another needle-leaved conifer, leaves attached singly, is fir (genus Abies). Here is some type of fir growing as an ornamental on the OSU campus. A fir tree on the OSU Columbus campus. February 19, 2010. Fir leaves are attached singly. Compared to those of spruce, fir leaves are soft, flat, blunt, and sweet smelling. That pleasant "pine-needle" sachet from the souvenir shop is probably a fir-neeedle sachet. Branch of ornamental fir on the OSU campus. February 19, 2010. Fir twigs, in contrast to those of spruce, are smooth. Fir leaf bases are expanded, looking like little suction cups. Fir twig. Eastern hemlock, Tsuga canadensis, is a native Ohio member of the Pinaceae that is locally abundant in cool ravines in unglaciated southern portions of the state. It's also a beautiful lawn ornamental. Here's one in the Clintonville neighborhood of Columbus. Eastern hemlock tree. February 15, 2010. Columbus, Ohio. Eastern hemlock leaves are flattened, and attached singly. The seed cone are small. They ripen in autumn and release their seeds during autumn and winter. Eastern hemlock. February 15, 2010. Columbus, Ohio. Eastern hemlock leaves are spirally arranged around the twig, but the upper and lower ones are splayed sideways, resulting in flattened sprays of foliage. Prominent paried white lines of stomates (breathing pores) mark the underside of each leaf. Like those of spruce, eastern hemlock twigs have a rough appearance owing to persistent leaf bases lying alongside the twigs. Eastern hemlock twig. The remaining evergreen member of the Pinaceae is not an Ohio native. This is Douglas-fir, Pseudotsuga menzeisii, the massive tree, overtopped only by the redwoods, that dominates conifer forests of the Pacific northwest and Rocky Mountains. The species is planted sparingly in parks and cemeteries. Here's one at Greenlawn, pretty wimpy, but Douglas-fir nonetheless. Douglas-fir at Greenlawn Cemetery. February 22, 2010. Eerily similar both to spruce (Picea) and fir (Abies), and with a genus name meaning "false hemlock," Douglas-fir can indeed be a fooler. Fortunately, a merciful natural selecter installed an easy identification module: seed cones that are most distinctive. Doug-fir cones have very long appendages (bracts) extending out above each of the woody seed-bearing scales. In other conifers, these bracts are so short as to be out of sight, obscured by the scales. Pseudotsuga cone bracts bear a whimsical resemblance to mice crawling into the cones, with only their back legs and tail protruding. Douglas-fir at Greenlawn Cemetery. February 22, 2010. Douglas-fir leaves are attached singly and spirally inserted, thus the tree looks much like spruce or fir. The texture of the twigs is intermediate between the roughness of spruce and the smoothness of fir. Douglas-fir leaves are singly attached, and spirally inserted on twigs that are a bit rough. Part 2: Cupressaceae, the Cypress family Members of the Cupressaceae bear small needle like or, more often, scale-like leaves that are opposite or whorled, crowded and often overlapping. Of the three northeastern U.S. genera, two occur naturally in Ohio: Thuja (northern whitecedar) and Juniperus (juniper). Missing is a species of Chamaecyparis, C. thyoides, Atlantic whitecedar, that occurs on the coastal plain. Atlantic whitecedar (spelled as one word because its really a cypress, not a cedar) and other species in the genus are cultivated ornamentals, so there must be some Chamaecyparis lurking about in Columbus but my efforts to track one down for this article have failed. Northern whitecedar (deliberately spelled as one word because it's really a cypress, not a cedar), found naturally in both wet fens and on dry limestone outcrops, is also a widely planted ornamental. Below, see planted whitecedars forming a semicircular backdrop of a little amphitheater on the OSU campus. (Note also the tallest tree in the backgound, a deciduous conifer, baldcypress (Taxodium distichum, family Taxodiaceae.) Northern whitecedar at OSU, Columbus, Ohio. February 7, 2010. Thuja produces little upright seed cones that are oblong, with overlapping scales. Northern whitecedar. February 7, 2010. The leaves of Thuja are "decussate," meaning that they are arranged leaves in opposite pairs that are perpendicular to one another. A further distinction is that the upper and lower leaves are flat, but the lateral ones are folded over, clasping the upper and lower ones. It reminds me of someone holding a big hamburger with both hands. Northern whitecedar leaves are scale-like and in overlapping pairs. Juniper, Juniperus virginiana, also called eastern redcedar (deliberately spelled as one word because it's really a cypress, not a cedar) is an extremely common and abundant conifer, especially in areas with calcareous soil. It has a distinctively dark pyrimidal form, commonly seen scattered in old fields, where it is a pioneer in secondary succession. Eastern redcedar. Marion, Ohio. February 15, 2010. Unlike most other conifers, which are monoecious, junipers are dioecious, i.e., having separate male and female individuals. The females bear highly modified cones that, having fleshy and fused scales, look quite berry-like. The "berries" of J. communis (common juniper, a shrubby species that occurs in Ohio, but is actually not very common) constitute the principal flavoring used in making gin. The word "gin" is derived from a modification of a French or Dutch word for "juniper." They are an important winter food source for many songbirds, including cedar waxwings. Female redcedar bearing berry-like seed cones, February 15, 2010. Eastern redcedar displays considerable variability in its foliage, often with both types on the same tree. The tiny scale-like leaves may either spread out from the twigs, or instead lay appressed against the twigs in the manner of Thuja. Here's a spreading-leaved sample. Eastern redcedar twig showing spreading-leaved form. ...and here's an appressed one. Eastern redcedar twig showing appressed-leaved form. Part 3: Taxaceae, the Yew Family. One local evergreen conifer doesn't produce cones. Taxus (yew, in the family Taxaceae) seeds are instead borne singly and look very berry-like, as they are provided with a fleshy covering at maturity. The fleshy part, a highly modified seed cone scale, is the only part of the plant that is non-toxic. Here's what a yew seed looked like in mid-summer several years ago. This is one of several very commonly planted ornamental Taxus species, perhaps English yew (T. baccata) or some Asian species. The native yew, T. canadensis, is an uncommon shrub in the understory of rich deciduous and mixed deciduous-conifer woods, occuring mainly in the northeastern portion of the state. Yew is indeed a gymnosperm (i.e., "naked-seeded") plant. Note that the seed is not enclosed by this fruity-looking structure; it is merely surrounded by it. Midsummer yew seed. July 31, 2005. Columbus, Ohio. Currently, the yew shrub seems a little more concerned with survival than reproduction. Yew shrub. February 15, 2010. Columbus. Ohio. The Playboy Mansion is being redecorated. The interior designer decided it would be nice to employ paint colors exactly matching those found on Mr. Hefner's favorite plant, if only it could be determined what that plant was. The designer, as luck would have it, was a pretty woman who decided to ask "Hef" for the name of his favorite plant. Expecting professionalism even from a well-known "womanizer," she was taken aback when he said "I love yew." Consequently she went to the gardener to find out what plant to sample the colors from, for the paint formulation. The gardener's advice was simple: "Use Hugh's yew's hues." Yew leaves are flat, and arranged in flat sprays much like eastern hemlock. Yew shrub. February 15, 2010. Columbus Ohio. Closeup, beneath, note that yew leaves bear two broad bands of stomates. The overall color is uniform, not white-striped as eastern hemlock. Yew leaves are uniformly colored beneath. Midwinter Fungi Jan.-Feb., 2010 Perhaps the most magnificant thing that nature ever selected, the "shotgun fungus," Pilobolus grows on the dung of grass-grazing mammals, including horses, cows and sheep. It's a member of the group of fungi called "zygomycetes" (Class Zygomycota). Zygomycetes are distinguished by having a coenocytic (multinucleate) mycelium (the threads that comprise the body of a fungus) from which extend upward, either as a result of a sexual or an asexual process, elongate swollen-tipped stalks, each topped by a case of spores, a sporangium. To experience Pilobolus, simply ask a farmer for a few dollops of sheep (or horse, or cow) poop. It helps if you provide her/him a container, such as a lettuce crisper, or a piece of "Tupperware." Let the poo sit, covered so that it stays moist, for a few days, then lift the lid and behold such extreme wonderfulness that redwoods, pandas and whales will hang their heads dejectedly upon the sudden realization that they are so enormously out-classed. Pilobolus adorns ovine dropping brought in from the barn. February 2, 2010. Pilobolus is neatly adapted for moving from one dung-patty to another. The swollen top of the sporangium-producing stalk (sporangiophore) is transparent and functions as a lens, enabling the sporangiophore to position itself at a low angle by pointing towards the rising sun. In this way the spores (packed together into the dark compressed "hat" at the very top of the stalk) are dispersed away from their home dung-pile when they are expelled ballistically as much as 6 feet away. This is necessary because grazing herbivores avoid dung as they merrily munch the nearby grass. While they munch the grass they also munch Pilobolus spores, and a new generation of fungus finds itself in just the right place to colinize (and help recycle) a new patch of dung. Pilobolus, the hat-tossing" fungus, orients towards the rising sun and shoots spores away from home. Another major group of fungi are the basidiomycetes, sometimes called "club fungi," in the Class Basidiomycota. This group includes mushrooms, one species of which is quite tiny, and grows from crevices in the bark of a sweetgum tree in front of my house. Photographing the mushroom is much more interesting than shoveling snow. I think this is Mycena corticola. The tiny "bark mycena" (Mycena corticola) mushroom, Orthotrichum pumilum moss and Candelaria concolor lichen growing on an urban sweetgum tree. February 6, 2010. Columbus, Ohio. Lichens are well known symbiotic dual organisms --an alga and a fungus. But they're really mostly fungus, and often display the characteristic fungal spore-producing structures --usually ascocarps --of their group, usually the sac fungi (Class Ascomycota). Here's Physcia millegrana growing on the bark of an American sycamore tree alongside the Scioto River in Columbus, Ohio. This is a narrow-lobed light gray foliose lichen that has fluffy-looking edges owing to its abundant marginal soredia --powdery granules containing both fungal hyphae and alga cells that break away from the lichen, enabling dispersal and reproduction. Note also the cup-shaped apothecia --fungal reproductive structures lined with microscopic spore-producing sacs (asci). Growing with the gray Physcia is a very common associate found even on roadside trees in urban areas, the bright yellow Candelara concolor. Physcia millegrana. Here's a little more Candelaria concolor, along with Tortula papillosa (family Pottiaceae) moss and a sycamore lace bug insect. Moss, bug and lichen. January 21, 2010. Columbus, Ohio. On a rock in a wooded area alongside the Scioto River, some quite small lichens are growing. One of these is a grayish-brown foliose one with narrow lobes. It's Phaeophyscia adiastola, mingling with Candelaria. Foliose lichens on rock. A couple other small lichens are "crustose" one. i.e., species lacking a lower layer (cortex) and that are so tightly adherent to the substrate that it is nearly imposssible to separate the lichen from it. This one, Caloplaca sideritis, bears abundant apothecia (cup-shaped ascocarps). The crustose lichen Caloplaca sideritis on rock. Another crustose lichen sharing rocky real estate with Caloplaca is even less conspicuous because its ascocarps are of a type called "perithecia," that are flask-shaped and sunken deep within the tissues of the lichen. All that are visible are the perithecia necks, seen as scattered black spots on the surface of the lichen, Endocarpon pallidum. Note also an Orthotrichum moss, and a bit more of the foliose Phaeophyscia. The crustose lichen Endocarpon pallidum.