RANUNCULACEAE – the buttercup family

by Adriana Lopez-Villalobos and Amelie Mahrt-Smith

The Ranunculaceae family is more commonly known as the buttercup family, which is reminiscent of some of the shiny yellow members of the Ranunculus genus. The buttercup family may be considered “simple” from an evolutionary standpoint, because the floral parts – the petals, sepals, stamens and pistils – are all distinct and not fused in any way. Moreover, reproductive parts are often of an indefinite number as compared to other plant families with predictable numbers of three, four, or five. Some flowers, such as in the columbine, delphinium and clematis have flowers that might look highly complex, but they are still considered “simple” because all the parts are independently attached. There is quite a bit of variation in this family in terms of the number of sepals (3-15), petals (0-23), and stamens; however, for identification, one common pattern to look for is the multiple pistils (3 to more) in the centre of the flower, each with its superior ovary (hypogynous). Some members of the Rose family also have multiple pistils, but they have a hypanthium, a cuplike structure from which the sepals, petals and stamens all arise (perigynous flowers). The leaves are also different in that the roses will often bear prominent stipules, a feature lacking in the Ranunculaceae (Elpel, 2004). For examples of these differences click | here |.

Over the last few weeks, we have seen several examples of species from this family in Kingston. This week we decided to give a turn to two species native to Canada: the red columbine and the Canada anemone.

Aquilegia canadensis (Canada columbine)

A garden favourite, this member of the Ranunculaceae family is native to North America! Aquilegia canadensis, also known as the red columbine, wild columbine, or Canada columbine in English, is probably more familiar as a colourful addition to a carefully tended garden than as a weed. Outside of the city, you may be able to find this short-lived, spring-flowering perennial plant on rocky outcrops, dry woods, slopes, ledges or open areas, but in urban areas like in Kingston, it has been mostly crowded out of untended space by more competitive invasive species like garlic mustard (Alliaria petiolata; see our Blog post from June 9th, 2020). It has been suggested that the name Aquilegia is derived from the Latin word Aquila, meaning Eagle, possibly because of the flower’s spurs’ resemblance to an Eagle’s talon.

 

Aquilegia canadensis along sidewalk
Aquilegia canadensis amongst the foliage in Kingston, ON.

Columbine flowers are showy and unique, each petal having a long narrow spur at the back. The leaves grow in leaflets of 3 with deep lobes. The Canada columbine can be differentiated from similar columbine species like the European columbine (A. vulgaris) by its scarlet flowers with a yellow centre, and its stamens, which are long and protrude from the flower; the European columbine’s flowers are typically blue, purple, or white, and their stamens are not protruding (Newcomb 1977). Canada columbines can grow in a wide range of well-drained soil and can tolerate moderate shade. As well, this species is said to have good resistance to leaf miner beetles, which often cause damage to other species of columbines. For some tips on growing A. canadensis in your garden, as well as a shortlist of some other columbine species native to Canada, see | here |

Two species of Aquilegia
Left: Aquilegia canadensis, native to North America; Right: Aquilegia vulgaris, the garden cultivar introduced from Europe.

The columbine flower produces nectar in its spurs, which attracts a variety of pollinators, including the ruby-throated hummingbird (Archilochus colubris). It is also a food source for the rusty-patched bumblebee, Bombus affinis, an endangered species of bumblebee native to Ontario whose numbers have declined due to several ecological factors, including habitat loss (Macior 1966). Although the rusty-patched bumblebee has not been seen in Ontario outside of the Pinery Provincial Park since 2002, there are many other native species of bumblebee that would appreciate some Canada columbines to snack on in your garden! This includes some threatened North American bumblebee species such as B. fervidus and B. pensylvanicus, as well as the hummingbird clearwing moth (Hemaris thysbe). Although it might seem logical to think that A. canadensis would reproduce primarily via outcrossing, genetic analysis using progeny arrays from populations across its range have shown that approximately 75% of its seed, on average, are the product of self-fertilization. Thus, Canada’s columbine has a mix-mating or selfing mating system, rather than outcrossing (Eckert and Herlihy 2004).

Queen’s Biology faculty member Dr Chris Eckert has investigated several aspects of A. canadensis life history, floral morphology, ecology and evolution; some of his research on A. canadensis conducted at the Queen’s University Biological Station can be found on the QUBS Research Projects website. In recent years, the genus Aquilegia has become a model system for the study of floral evolution and development because of its unusual floral morphology and the recent explosion in the number of species associated with pollinator shifts and other ecological factors. To take advantage of these features, a collaborative group has developed several genetic and genomic resources that have facilitated the study of the genetic basis of these morphological innovations (Kramer 2009).

Canada Anemone (Anemonstrum canadense)

The Canada anemone, or ‘windflower’, is an inconspicuous member of the Ranunculaceae family in flower this month. They are not quite as abundant in urban areas as some other introduced ranunculus species, such as the common or tall buttercup (Ranunculus acris), the creeping buttercup (Ranunculus repens), or other common garden escapees, but you may still stumble across this low white flower in the Kingston area. The name ‘anemone’ is an Ancient Greek word meaning ‘daughter of the wind’. Ironically, this species prefers sites protected from wind since strong winds can bend or break the thin flower stalks.

This species was, until recently, part of the Anemone sensu lato (in the broad sense) genus and is often still called by its synonym Anemone canadensis. However, recent molecular phylogenetic analyses revealed that there were many more species and genera that needed to be included in the genus to satisfy the criterion of monophyly. Instead of renaming hundreds of species and including morphologically different genera such as Clematis (virgin’s-bower), Pulsatilla or Hepatica, the Anemone genus was regrouped into several genera, one of them being Anemonastrum, where Canada anemone is currently placed (Mosyakin 2016).

Canada anemone
The Canada anemone along the wet, rocky shores of Lake Ontario in Kingston.

The leaves of the Canada anemone have 3-5 deep lobes and toothed edges, and they have long stalks that emerge from a clump at the base. The flowers are white with many yellow stamens in the centre bearing pollen that attract pollinators. The notable features of the flower are the white petal-like sepals, usually 5 per flower. Sepals are a division of the outer part of the flower called the calyx and are often green and resemble leaves; whereas petals are a division of the inner part of the flower called the corolla and are often showy and attract insects. In A. canadense there are only sepals (modified to look like petals) and the petals are absent.

closeup of the Anemone flower
A closeup of the Anemone flower – notice the five white sepals and numerous yellow stamens.

The Canada anemone typically inhabits river margins, low moist meadows,and thickets. In nature, it can be found growing in massive colonies, and in cultivated areas is a common garden escapee. It is distributed throughout southern Canada from Newfoundland to British Columbia and in the U.S from Maine to Montana south to West Virginia, Missouri, Kansas and scattered through the Rocky Mountains to New Mexico. It is a perennial that can grow in semi-shaded areas and makes a beautiful addition to gardens while also benefitting the ecosystem by supporting native pollinator communities! Keep an eye out for this wildflower throughout the summer months around Kingston, ON – it is more than just a weed.

Ethnobotanical and medicinal uses

A predominant property in the plants of the Buttercup family is an acrid protoanemonin glycoside oil. Most of the species are listed as poisonous, but most are safe to taste, as long as you spit it out! The buttercup taste is biting and acrid, and its strength varies between species. The acrid properties of the buttercups are unstable and are destroyed by drying or cooking, so the very mild buttercups are edible as salad greens or potherbs. Plants in the buttercup family have been studied for possible medicinal use since the 1900s. The chemical compound protoanemonin has irritant but also antibiotic properties. The Pawnee peoples of what is now Oklahoma used A. canadensis to treat headaches, and closely related species had medicinal uses ranging from topical wound care to reviving unconscious people (Turner 1984). A. canadense was used by many Indigenous peoples in medicine. Traditional knowledge about the plant’s properties and how to prepare them for medicinal use is paramount – one risks further discomfort and injury from improper use of traditional medicine. The Ojibwe, an Anishnaabe peoples who have inhabited the Great Lakes region for thousands of years, used A. canadense and other closely related species of Ranunculaceae as a poultice or wash to treat superficial wounds, as a remedy for colds and headaches, and for the revival of unconscious people (Turner 1984).

Using herbarium specimens to understand phenology

As the negative impacts of human activities on ecosystems become deniable, and more pressing to attend than ever, researchers need biological data spanning hundreds of years to understand how anthropogenic drivers affect biodiversity and natural resources. Changes in the timing of key life-history events, such as reproduction (flowering and fruiting) are among the most obvious and well-documented species responses to climatic change, especially for plants. In recent years, the scientific community has started to turn their attention to hundreds of millions of plants, fungal and animal specimens deposited in natural history museums as a potential source of these data. The increasing number of museum specimens becoming available online combined with newly developed web-enabled crowdsourcing platforms (i.e. CrowdCurio) and protocols for scoring and analyzing phenological data provide unparalleled access to ecological and evolutionary data spanning decades and sometimes centuries. Park et al. (2019) capitalized on the snapshots of phenology (i.e. flowering and fruiting) that herbarium specimens offer to increase the spatial, temporal and taxonomic diversity of phenological studies. They used 7,722 herbarium specimens from 30 flowering plant species with varying life-history traits, growth forms, native status and general reproductive seasonality (e.g. early- versus late-spring flowering), spanning 120 years and modelling to understand how phenology changes in response to climate change. Their study included the red columbine and Canada anemone!
Their results showed that early-flowering species flowered and fruited earlier in response to warmer spring temperatures and that the magnitude of these responses varies significantly between and within species across their latitudinal ranges. They also found that fruiting in populations from warmer, lower latitudes are significantly more phenologically sensitive to temperature than that for populations from colder, higher-latitude regions.

By bringing you these bits of information from the scientific literature we want to raise awareness of these unparalleled resources. Herbaria and natural history museums are under constant threat owing to budget cuts and other institutional pressures. Like the study by Parker et al. (2019), more publications out there are shedding light on the unique discoveries that are possible using museums specimens, and thus, pointing to the singular value of natural history collections in a period of rapid change.

References

  1. Eckert, C.G., Herlihy C.R. 2004. Using a cost-benefit approach to understand the evolution of self-fertilization in plants: the perplexing case of  Aquilegia canadensis  (Ranunculaceae). Plant Species Biology 19:159–173
  2. Elpel, T. J. 2004. Botany in a Day: The Patterns Method of Plant Identification. HOPS Press.
  3. Kramer, E. M. 2009. Aquilegia: A new model for plant development, ecology, and evolution. Annual Review of Plant Biology 60: 261 – 277.
  4. Macior, L.W. 1966. Foraging behavior of Bombus (Hymenoptera: Apidae) in relation to Aquilegia pollination. American Journal of Botany 53: 302 – 309.
  5. Mosyakin, S.L. 2016. Nomenclatural notes on North American taxa of Anemonastrum and Pulsatilla (Ranunculaceae), with comments on the circumscription of Anemone and related genera. Phytoneuron 79: 1 – 12.
  6. Newcomb, L. 1977. Newcomb’s Wildflower Guide. Little, Brown and Company. New York. pp. 228.
  7. Park D. S., Breckheimer I., Williams A. C., Law E., Ellison A. M., Davis C. C. 2018 Herbarium specimens reveal substantial and unexpected variation in phenological sensitivity across the eastern United States. Phil. Trans. R. Soc. B 374: 20170394.
  8. Turner, N.J. 1984. Counter-irritant and other medicinal uses of plants in Ranunculaceae by native peoples in British Columbia and neighbouring areas. Journal of Ethnopharmacology 11: 181 – 201.

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