Ars Plantarium (The Art of Plants)

The Art of Plants

Salix (willow)

Salix nigra illustration by Paul Landacre
(circa 1948) Spring promises are exemplified by the black willows (Salix nigra Marshall). From a distance, they provide the first hint of green in wetlands along rivers and creeks. Close up, emerging leaves expand from a micro-template within the dormant buds. The mature leaves (left) are an illustration by Paul Landacre (circa 1948) in Donald Culcross Peattie's A Natural History of North America Trees. Peattie emphasizes the importance of black willows for protecting river banks from erosion.

willow bud break (circa 27 March through 06 April 2021) Some examples of bud break (circa 27 March -- 02 April 2021 and circa 27 March -- 06 April 2021): willow bud break (circa 27 March through 02 April 2021)

willow inflorescences (circa 15 through 26 April 2021) and willow stipules and leaves beginning to unfold (circa 08 April -- 10 April 2021), followed by catkin-like inflorescences (female for this tree) (circa 15 April -- 26 April 2021): willow bud break (circa 08 April through 10 April 2021)

Buds (tree buds)

dormant redbud bud (circa 05 January 2021) sugar maple bud breaking dormancy (circa 1969) With winter cold, not much growing but a lot of dormancy, including dormant buds on trees. With spring, the buds will break dormancy, releasing either flowers, or leaves, or both. Changes in color and size anticipate the explosion of flowers and leaves --such as the sugar maple (Acer saacharum Marshall) (right) (circa 1969) from Harlow and Harrar's Textbook of Dendrology (5th edition), and redbud (above).

Some examples of dormant tree buds: Apple (Pyrus malus L.) and Silver Maple (Acer saacharinum L.) dormant apple buds (circa 09 January 2021) dormant silver maple buds (circa 14 January 2021)

Hackberry (Celtis occidentalis L.) and Willow (Salix nigra Marshall) dormant hackberry buds (circa 13 February 2021) dormant willow buds (circa 11 February 2021)

Willow (Salix nigra Marshall) breaking bud early in the spring (circa 27 March 2021) willow buds breaking dormancy (circa 27 March 2021)

Mycophycophyta (lichens)

lichens encrusting a branch (circa 30 October 2020) Although the taxonomic term Mycophycophyta evokes the symbiotic relation between a fungus (Mycota, usually an Ascomycota) and an algae (Phycophyte, usually a Chlorophyta), it implies a unique genetic identity, so many lichenologists think the taxonomic term is misleading and call them just lichens --totally cool and unique.

Lecanora lichen enveloping a branch (circa 17 October 2020) Lecanora encrusting a branch shows the ascomata from which lichen spores are released.

schematic showing intergrowth of fungus and algae in a lichen (circa 1911) The intertwining of fungal mycelium and algal cells are shown in a diagram from Bergen's Practical Botany (circa 1911).

Xanthoria growing on weathered concrete (circa 21 October 2020) Lichens can grow on many harsh substrates, such as stone and concrete.

Lichens growing on silver maple (circa 29 October 2020) When looked at close-up, lichens can certainly exhibit artistic flair!

Lichens growing on silver maple (circa 29 October 2020)

Helianthus (sunflower)

sunflower inflorescence (circa 17 July 2020)

sunflower woodcut (circa 1581) sunflower opening (circa 12-17 July 2020) Helianthus annuus L. is an Asteraceae originally cultivated by native Americans in regions surrounding the confluence of the Ohio and Mississippi rivers. Now, it is grown as an oil seed crop throughout the world. The flowers are quite large and bloom from mid-summer (right).

sunflower stylar structure (circa 1974 and 2020) The flower is a composite of many flowers. Ray flowers look like petals and disc flowers form the 'eye' of the composite flower. The disc flowers mature from the outside to the inside (right).

Striking images of the sunflower were created by Vincent Van Gogh (circa 1888-1889)(below).

Sunflowers by Van Gogh (the Arles series --circa 1888-1889)

Taraxacum (dandelion)

Pasture blooming with dandelions (circa 25 May 2020) Opening dandelion flowers --mid-morning dandelion illustration by H. Herincq (circa 1895) Taraxacum officinale F.H. Wiggers is a cosmopolitan weed closely associated with the human species. It grows abundantly on disturbed sites (such as pastures, above). It survives adversity (including weeding) quite well, due in part to its root(s), from which the aboveground basal leaves and flowers can readily regenerate. The deep taproot is shown in the botanical illustration (right) --from Annales des Sciences Naturelle Botanique (circa 1895)-- drawn by B. Herincq.

Opening dandelion flowers --mid-afternoon

The flowers bloom from mid-morning to late afternoon, and attract a wide diversity of insect pollinators. The flower is actually an tightly compact inflorescence --comprised of many flowers-- a common feature of the Asteraceae.

The dandelion's reputation is in the eye of the beholder. To some, a noxious weed. To some, a delicacy to garnish a salad. To others, a beautiful splash of yellow in early spring (above), followed by the silver of the seedheads (below).

Pasture with post-bloom dandelions (circa 29 May 2020)

Conzya (horseweed)

Horseweed in the foreground of a soybean field (circa 2019) single Conzya canadensis plant in a soybean field Conzya illustration by Johann Sturm (circa 1796) Conzya canadensis (L.) Cronq. (formerly Erigeron canadensis) is a north american species commonly found on disturbed sites. The botanical illustration (right) comes from Deutschlands Flora in Abbildungen (circa 1796), drawn by Johann Sturm.

Conzya inflorescences: from buds to seeds

In the United States and Canada, it is a major concern for soybean farmers: Conzya-infested fields have significantly lower crop yields. Since it is becoming resistant to glyphosate (Round-Up), it is an especial problem for farmers using no tillage techniques to minimize soil erosion.

In the late summer, as the soybean crop matures, the Conzya canadensis plants are very easy to see, towering over the soybean in colonies of various sizes. The seeds are readily wind dispersed, one of the reasons (in addition to inadvertent dispersal by humans) that it has spread throughout the globe as an invasive weed.

Global distribution of Conzya canadensis (circa 1600-2019)

Cercis (redbud) redux

Cercis seed anatomy by Michel Afanasiev (circa 1944) developing first leaf on a Cercis seedling Redbud (Cercis canadensis) has already been documented on ars plantarium (Cercis (redbud)). Over the winter, about 50 seeds were harvested from a local tree. One of the seeds broke dormancy this spring (right), creating an opportunity to document leaf development soon after germination.
As described by Michel Afanasiev (circa 1944), like many leguminous trees, Cercis canadensis seeds (left) are very dormant: because of both an impermeable seed coat and a highly dormant embryo. So even if the seed coat is treated --either mechanically or with acid-- so that the seed can imbibe water, the embryo will still remain dormant for an extended period of time.

developing second leaf on a Cercis seedling developing third leaf on a Cercis seedling

The second (left) and third (right) leaves emerge in a zig-zag pattern of leaf development that is retained as the tree grows.

In its natural shaded habitat, the mature leaves cover almost 100% of the area in a plane to maximize the capture of light for photosynthesis (below).

mature leaf coverage on a shaded Cercis tree

Rumex (curled dock)

Rumex crispus (curled dock) plant (circa 18 July, 2017) Curled dock (Rumex crispus) is a common roadside perennial plant, distinctive for its brown coloration as the seeds mature in mid-summer. Rumex seed development (circa 18 July 2019) Although the leaves can be eaten, they tend to contain high levels of oxalic acid (hence mouth-puckering). Rumex is a major genus in the Polygonaceae family, a family that includes knotweeds, buckwheat and rhubarb.

The botanical illustration by Norman Criddle (lower left) is from a 'modern' publication: Farm Weeds of Canada by CJ Clark and J Fletcher (circa 1906). The fanciful illustration (lower right) of garden sorrel (Rumex acetosa) is from a Book of Hours by Jean Bourdichon (circa 1505-1510).

Rumex botanical illustration by N Criddle (circa 1906) Rumex illustration from a Book of Hours by J Bourdichon (circa 1505-1510)

Trifolium (white clover)

White clover (Trifolium repens) blooming (circa 12-28 June 2019)

White clover (Trifolium repens) leaf emergence (circa 26 June 2019) White clover (Trifolium repens) leaf emergence (circa 12 June 2019) White clover (Trifolium repens) is a cosmopolitan forage legume deliberately planted in pastures, and common in lawns, roadsides, and other disturbed sites. It spreads by recumbent stems growing at the soil interface, leaves are initiated at regular intervals and grow to a height of about 5-10 cm.

bee pollinating white clover (Trifolium repens) (circa 4 July 2019) Inflorescences appear in early to mid-summer. Many bee species (including honeybees) pollinate the flowers. Clover honey (Ontario No. 1 white/blanc) is one delicious product of clover meadows.

Eventually the seed pods will mature and seeds will be dispersed to germinate in fall or spring. White clover (Trifolium repens) seeding (circa 30 June through 4 July 2019)

Agaricales (gilled mushrooms)

gilled mushroom cap (circa 6 August 2018)

ripening mushrooms (circa 6 August 2018) Agaricus from a France flora by Jean Baptiste Bulliard (circa 1786) Agaricales (the gilled mushrooms) includes both edible and highly poisonous mushrooms. Anywhere there is organic matter to feed on, they are likely to appear, often after prolonged rain (right). Jean Baptiste François Pierre Bulliard (Pierre Bulliard) was one of the first botanists to provide a comprehensive survey of gilled mushroom species in France (left) (circa 1786).

ukiyo-e print by Hiroshige of mushroom hunters in Kumano (circa 1860) There is a long tradition of mushroom hunting in human society. The examples shown here are the Mushroom Hunters of Kumano (a ukiyo-e print from the Japanese artist Hiroshige Utagawa (left), (circa 1860) and mushroom gathering in the forest by the Russian impressionist Sergei Vinogradov (below) (circa 1927).

Mushroom gathering in the forest by Sergei Vinogradov (circa 1927)

Cercis (redbud)

Cercis canadensis dormant buds during winter (circa January through April, 2018)

Cercis canadensis flower bud break (circa May 2018) Cercis canadensis leaf emergence (circa May 2018) Redbud (Cercis canadensis) is an understory tree of southernly forests, but does extend north into Heartland (southwestern) Ontario. Over the winter months, the buds must survive snow, hoarfrost, ice, and temperatures that drop below zero Fahrenheit (-20 Celsius) (montage above). Once warm temperatures arrive, the flower buds break dormancy and start to unfold (montage at right). Soon, the leaves at the branch tips follow suit (left).

Cercis canadensis illustration by Paul Landacre (circa 1948) Donald Culcross Peattie's A Natural History of North America Trees (illustrations by Paul Landacre)(circa 1948) provides some of its natural history. George Washington transplanted redbud from the woods to his garden for its early spring blossoms.

Cercis canadensis flower (circa 18 May 2018)

Peattie also writes that redbud was mentioned by John Lawson (A New Voyage to Carolina (circa 1709)) for the use of its blossoms in spring salads ("The Red-Bud-Tree bears a purple Lark-Heel, and is the best Sallad, of any Flower I ever saw. It is ripe in April and May."). Redbud flowers are still considered a delicacy today.

Redbud is a welcome sign of spring.

Cercis canadensis flowering branch (circa 20 May 2018)

Medicago (alfalfa)

alfalfa field in bloom (circa July, 2017) alfalfa root development (circa 1922) Alfalfa (Medicago sativa) is a perennial forage crop, usually cut, dried, baled, and stored to feed dairy cattle over the winter months. Alfalfa was originally domesticated in Iran millennia ago, and is a preferred forage crop because of its high protein content. Like many legumes, the roots grow very deep (and quickly). There is a symbiotic relation with nitrogen-fixing bacteria (Rhizobia) in root nodules that provide nitrogen for protein production. Thus, alfalfa enriches the soil as a byproduct of its growth. The root illustrations are attributed to Miss Annie Morgensen and Mrs. F.C. Jean in Development and Activities of Roots of Crop Plants. A Study in Crop Ecology By John E. Weaver, Frank C. Jean and John W. Crist (circa 1922)(published by the Carnegie Institution of Washington --Publication No. 316). Inflorescences, flowers and pods are shown below.

alfalfa inflorescences (circa July, 2017) alfalfa flowers (circa July, 2017) alfalfa spiral pods (two and three coil) (circa August, 2017)

Alfalfa harvest. alfalfa windrows in the field (circa July 28, 2017), then raked for further
drying (circa July 30, 2017), and baled (circa Juy 31, 2017

Galium (bedstraws)

Galium mollugo plant (circa June, 2017)

Galium aparine growing tip (circa June, 2017) Galium aparine from Britton and Brown (circa 1913) flowers and fruits of Galium aparine (circa June, 2017) Galium (bedstraws) are a common herbaceous plant of woods and meadows. A member of the Rubiaceae family, but unlike Coffea (coffee) they have little economic value,. They may have been used for bedding per their common name (bedstraws). Many of the species have minute barbs, that allow them to cling to each other in a three-dimensional network. axillary fruits of Galium aparine (circa June, 2017) Wikipedia lists some of the names for a common barbed species (Galium aparine --shown above and to the right): cleavers, goosegrass, catchweed, stickyweed, robin-run-the-hedge, stickeljack, and grip grass, et cetera. The names give a practical idea about the grip of the barbs.

A non-barbed species (probably Galium mollugo) is shown to the left. It has been tapped by a xylem sap sucker, a spittlebug so named because of the spit-like residue it produces when feeding.

Gleditsia (honeylocust)

Locust leaf emergence (circa May, 2017)

Red eyed vireo on a locust branch (circa
1832) by John J. Audubon silhouette of locust tree (circa
1917) in Native Trees of Canada by R.C. Hosie Honeylocust (Gleditsia tricanthos) is a common tree --from the legume family-- that comes in two varieties, either thorned or thornless. The thornless variety (inermis) is commonly planted as a shade tree. The tree silhouette of a honeylocust tree on the left comes from Native Trees of Canada by R.C. Hosie (circa 1979). The honeylocust branch on the right (with a red eyed vireo) comes from the Birds of America by John J. Audubon (circa 1832).

The horticultural varieties have only staminate (male) flowers, so they don't produce the legume fruit pods.

inflorescence of honeylocust showing male (staminate) flowers

Carbon dioxide (photosynthesis)

Carbon dioxide elevations (circa August, 2016)

Charles David Keeling (Scripps Institution of Oceanography) measured carbon dioxide concentrations for extended periods of time in a number of locations around the world. The best known data are from Mauna Loa, Hawaii (red). The steady rise in carbon dioxide concentrations has been a key observation in support of 'global warming', since elevated atmospheric carbon dioxide acts to 'trap' long wave IR radiation, resulting in elevated atmospheric temperatures (the greenhouse effect). There are noticeable yearly 'wiggles' in the data series. The annual fluctuation is very large at northern latitudes (Point Barrow, Alaska data, upper blue), smaller in magnitude at mid northern latitudes (Mauna Loa, Hawaii, middle red), and absent in southern latitudes (Argentina, lower black). The annual fluctuation is due to seasonal variations in photosynthesis and respiration of terrestrial plants (northern latitudes contain most of the earth's land mass). Normally, the yearly cycles are well balenced, since the magnitude of the fluctuation is little changed, even as carbon dioxide concentrations have increased. The data are clear evidence for the Power of Photosynthesis in biotic control of the earth's environment.

Data source:

Triticum (wheat)

winter wheat flowering in an Ontario field (circa 4th June, 2016) Early summer flowering of a winter wheat variety of Triticum aestivum in an Ontario field (circa 2016).

Triticum aestivum: From The Genera of Grasses of the United States (circa 1920) (by A.S. Hitchcock). The illustrations were drawn by Mary Wright Gill (habit) and Agnes Chase (spikelet and spike details). Hittchcock's Genera of Grasses of the US --wheat illustration by Gill and Chase-- circa 1920

Harvesting grain (possibly wheat) in ancient Egypt (circa 1350 BCE). The illustrations were drawn by an unknown tomb painter. Grain harvest from the Menna tomb (TT69) circa 1350 BCE

Zea (maize)

maize seedlings in an Ontario corn field (circa 2016) Zea mays seedlings in an Ontario corn field (circa 2016).

Zea mays: From De Historia Stirpium (circa 1542) (Leonhart Fuchs' herbal with illustrations drawn and printed from nature by Albrecht Meyer, Heinrich Füllmaurer, and Veit Rudolph Speckle) and New Kreuterbuch (circa 1543). Zea mays (Fuchs circa 1540's)

Maya and Aztec Gods of Maize (circa 715 and 1400) Originally domesticated in Central America, Zea mays was deified by both the Mayans and Aztecs. The Mayan Maize God is emerging from the earth, assisted by his twin sons who are watering him (circa 715). The Aztec God is a modern sculpture by Angel Ceron based on a depiction in the Codex Borgia (circa 1400).

Sources: and

Cornus (dogwood)
Cornus leaf buds breaking dormancy

Cornus alternifolia in Ontario (circa 2016): Bud dormancy break in early spring.

Cornus alternifolia (Sargent circa 1892) Cornus alternifolia from Sargent's Silva of North America (circa 1892): Drawn by Charles Edward Faxon.

Cornus alternifolia in Ontario (circa 2016): Leaf emergence in early spring Cornus alternifolia leaves emerging in early spring

Glycine (soybean)
Soybean from Kaempfer's Amoenitatum Exoticarum (circa 1712)

Glycine max (circa 1712): An illustration from Kaempfer's Amoenitatum Exoticarum introducing soybean to Europe.

soybean (N.J. von Jacquin circa 1770) Glycine max (?) from von Jacquin's Hortus botanicus (circa 1770): Drawn by Franz Anton von Scheidel.

Glycine max in Ontario: seedlings at the beginning of the growing season (circa 2016) and mature plants ready for harvest (circa 2015). Soybean is commonly planted in rotation with corn on Ontario farms. Soybean seedlings (circa 2016) and mature plants ready to harvest (circa 2015 fall)

Solidago (goldenrod)
goldenrod (Marie-Victorin Flore Laurentienne circa 1935)

Solidago canadensis from Frere Marie-Victorin's Flore Laurentienne (circa 1935): Drawn by Frere Alexandre Blouin.

Solidago_canadensis_Step and Bois (circa 1897) Solidago canadensis (circa 1897): An illustration from Favourite Flowers of Garden and Greenhouse (E Step and D Bois)

Solidago canadensis in Toronto (circa 2015): Canadian goldenrod has a global distribution. Solidago_canadensis (circa 2015): plant and inflorescence detail

Coronilla (crown vetch)
Crown vetch (Clusius's plantarum historia circa 1601)

Coronilla varia (as Securidacae) from Clusius's Rariorum plantarum historia (circa 1601): Crown vetch.

Coronilla_varia_Peterson (circa 1968) Coronilla varia (circa 1968): An illustration by Roger Tory Peterson from A Field Guide to Wildflowers of Northeastern and North-central North America (Roger Tory Peterson and Margaret McKenny)

Coronilla varia in Toronto (circa 2015): Crown vetch was introduced as ground cover to prevent erosion, but can be an aggressive weed. Here are inflorescences at different developmental stages. Coronilla_varia_flowers (circa 2015): umbel inflorescence

And here are the developing compound leaves. Centaurea_varia_leaves

Centaurea (knapweed)
Blew-Bottle (Gerard's Herball circa 1636)

"Cyanus maior" from Gerarde's Herball (circa 1636): Great Blew-Bottle --related to knapweed (Centaurea).

Centaurea montana (circa 1790) And Centaurea montana (circa 1790): An illustration by Sydenham Edwards from Curtis's Botanical Magazine (source: Kew Botanic Garden website)

Centaurea nigra in Toronto (circa 2015): Knapweed is beautiful, cosmopolitan, but can be an aggressive weed. Centaurea_nigra (circa 2015): composite inflorescence

Centaurea nigra from the Illustrated Companion to Gleason and Cronquist's Manual (1998): by Noel Holmgren. This illustration was drawn by Lucille E. Kopp (circa 1948). Centaurea_nigra (circa 1948): illustration by Lucille E. Kopp

Centaurea_nigra (circa 2015): base of composite inflorescence

Plantago (plantain)
Plantago minor (circa 1430)

Plantago minor from Herbarum Vivae Eicones (circa 1530): Otto Brunsfels' herbal with illustrations made from nature by Hans Weiditz.

Plantago minor (circa 1450) And from De Historia Stirpium (circa 1542): Leonhart Fuchs' herbal with illustrations drawn and printed from nature by Albrecht Meyer, Heinrich Füllmaurer, and Veit Rudolph Speckle.

Plantago lanceolata (circa 1998) Plantago lanceolata from the Illustrated Companion to Gleason and Cronquist's Manual (1998): by Noel Holmgren. This illustration was drawn by Walter Lincoln Graham (circa 1940's).

Plantago major from Toronto (circa 2015): The flowering plant and inflorescences at bud, flowering and fruiting stages. Plantago major (circa 2015): plant and spike inflorescence

Sonchus (sow thistle)
Sonchus arvensis (circa 1885)

Sonchus asper from A Curious Herbal (circa 1737): Elizabeth Blackwell drew, engraved and coloured her illustrations for her herbal of medicinal plants.

Sonchus arvensis drawn by C. Sepp And Sonchus arvensis from Flora Batavia (circa 1800): illustration by Christiaan Sepp.

Sonchus arvensis (circa 1940) Sonchus arvensis from the Illustrated Companion to Gleason and Cronquist's Manual (1998): by Noel Holmgren. This illustration was drawn by Walter Lincoln Graham (circa 1940's).

Sonchus arvensis from Toronto (circa 2015): Inflorescences at bud, flowering and fruiting stages. Sonchus arvensis bud, flowers and fruit

Cyperus (sedge)

Cyperus alternifolius (Umbrella Sedge) Flowers. Cyperus (sedge) flowers

The diagrams come from Lawrence (1951) Taxonomy of Vascular Plants. Marion E. Ruff was the illustrator. sedge illustrations by Marion Ruff

Here are higher magnification images of the flowers and isolated pollen. Cyperus (sedge) flowers and pollen (high magnification)