Watching Winter Aconite, a Spring Emphemeral

In March, here in Ithaca, NY, spring is a pop-up affair. Bright yellow winter aconite suddenly illuminate muddy earth and sludgy leaves. Spring ephemerals, winter aconite vanish as soon as they have finished their work, so it is best to watch their behavior carefully while you have the chance.

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Winter aconite remain closed on rainy, gray days.

When the sun is out, and I can’t resist being out also, there they are: golden bowls lifted off the ground on short but sturdy stalks,  embellished by a distinctive green ruff. The flowers open and close depending on temperature and light conditions.

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It’s a sunny day!

Winter aconite flowers benefit the first pollinators of spring. Each flower is a “goblet” offering sugary nectar and pollen, vital food for the first foraging bees of the season.

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A whorl of anthers sit above a whorl of funnel-shaped nectaries. Greenish  carpels (ovaries) are visible at the center, tilted to the right.

Polish researchers Krystyna Rysiak and Beata Żuraw discuss many aspects of the flowers in their study “The Biology of Flowering of Winter Aconite.” Like the hellebore, their close relative in the buttercup family (Ranunculaceae), winter aconite guide honey bees to their pollen and nectar through scent and the reflection of UV rays. Each flower has on average 29 stamens, which shed pollen copiously for only 2-3 days, so the bees have to watch for visiting opportunities, and 3-6 funnel-shaped nectaries, which produce on average 1.23 mg nectar per flower. The concentration of sugars in the nectar averages 72.11%.  In the 75 or so open flowers I observed on the one sunny day this week, I only noticed one bee. I went inside to get my iPhone and when I came back it was gone and did not return. It was a sunny but windy day. According to the Polish researchers, honey bees prefer sunny windless days.

Botanically, the winter aconite flower is not what it appears. The yellow “petals” are actually sepals, having become petal-like,  and the nectaries are considered modified petals. The “Elizabethan” ruff leaves are considered “stem” leaves, while “true” leaves emerge after flowering.

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The funnel-shaped nectaries are clearly visible in this photo.

Once the bees have been fed, the flowers complete their reproductive cycle, offering up seeds when mature in lacily veined  “chalices” (carpels or ovaries), to continue the goblet metaphor.

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Mature carpels (ovaries) open to release seeds. Photographer: Rüdiger Kratz (Wikimedia Commons).

Botanical illustrations often clarify the confusing relationships of floral parts seen in photographs. The floral diagram (number 7 in the image below) shows five carpels (ovaries) surrounded by many anthers (two circles end to end). The outer ring of heart-shaped symbols represents the nectaries.

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Original book source: Prof. Dr. Otto Wilhelm Thomé Flora von Deutschland, Österreich und der Schweiz 1885, Gera, Germany
Permission granted to use under GFDL by Kurt Stueber
Source: www.biolib.de

In Lublin, Poland, the flowering period recorded during Rysiak and Żuraw’s study lasted from February 5th to March 22nd. This is a good long spell for foraging bees. Here in Ithaca I suspect the duration of flowering is much shorter, but I will have to record dates.  The researchers noted that snowfall did not injure blooming buds.

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This flower will reopen when conditions improve. [By Goranpavic (Own work) [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)%5D, via Wikimedia Commons]

Winter aconite has been cultivated since 1570, and its small tubers are readily available in bulb catalogues and garden centers for fall planting. They also naturalize by seed, creating cheerful, golden patches that are good for us and the bees. They are the gardener’s friend for two reasons: they repel deer and they can colonize under black walnuts, whose secretions of allelopathic chemicals deter many species from growing within their root sphere.

There is one very large patch in Ithan Valley Park (Radnor Township, Pennsylvania) that horticulturalist Carolyn of Carolyn’s Shade Gardens calls “a wonder of nature.” Carolyn writes that “There is so much yellow that I think it must be visible from outer space.” Be sure to scroll all the way down to the end of her post. The patch was originally part of an arboretum belonging to botanist John Evans (1790-1862). The biographical entry in the History of Delaware County, Pennsylvania, From the Discovery of the Territory Included within its Limits to the Present Time, With A Notice of the Geology of the County AND Catalogues of its Minerals, Plants, Quadrupeds and Birds, Written under the Direction and Appointment of the Delaware County Institute of Science (1862) by George Smith, M.D., portrays a lovely man who earned his living in the milling business while pursuing horticulture and natural history as an avocation:

Being almost shut out from social intercourse, our young miller, after having attended closely to his business on week days, spent much of his time on Sundays, in rambling over the wild and romantic country that surrounded his mill–in traversing its streams and in scaling its precipices. It was in this state of isolation from civilized society that the habits and tastes of John Evans underwent a change. It was in these solitary rambles that he laid the foundation of his character in after life. Here he became a devoted lover of nature, acquired the habits of close observation, and fitted himself for the successful study of the natural sciences.

Evans  became a well-respected amateur botanist, maintaining an extensive correspondence with like-minded people in Europe, including Sir William J. Hooker, Director of Kew Gardens. In exchange for American plant material, he received European material from Sir William. Perhaps tubers of winter aconite, considered native to southern Europe and east to Asia, were included in these exchanges.  Plant hunter Joseph D. Hooker, Sir William’s son, shared seeds from his Himalayan expedition of 1847-1851. Evans was interested in local flora as well and traveled extensively in the United States on collecting trips. A devoted horticulturalist, Evans used saw dust from his mill to mulch his extensive collection of local and exotic plants and is described as dying somewhat prematurely from a “consuming disease” after too much “exposure” in his garden.

Because winter aconite are so agreeable, they get a fair bit of press. The Guardian featured the winter aconite in their  Plant of the Week column in 2017. The column offers useful horticultural advice and a lively Comment field. ‘HumptyDumpty’, the first to comment, offered this story:

The novelist Anthony Powell was once at Buckingham Palace receiving some medal or gong, and when he went into the investiture room where the Queen awaited him, gong/medal in hand, she wished him a good February morning, enquired where he lived (“in the country, your Maj, near Frome)”, and she then asked:

“Do you have aconites?”

AP, wondering what the bloody hell they were, decided they must be some unpleasant but not fatal medical condition, possibly related to piles, so answered:

“not as yet, your Majesty, although at my time of life I find a careful diet is advisable”

A careful diet should include the omission of winter aconite. Closely related to the beautiful but deadly garden plant monkshood (Aconitum sp.), they are full of cardiac glycosides. ‘Wolf’s bane’ and ‘queen of poisons’ are some of the common names for monkshood.

As I watch winter aconite responding to the vagaries of late winter-early spring weather, open and closing with the changes in temperature and sunlight, I become more attuned to changes everywhere. I also realize how much weather can influence a successful relationship for the winter aconite and the honey bee. When the weather is bad, as it has been all this week, the flowers are closed and the bees are absent. (I need to find out more about how the bee benefits the winter aconite. It seems probable that they can self-pollinate, but cross-pollination is always a good thing.)

I am happy with my small patches of winter aconite. They are close at hand where I can keep my eyes on them–right by the back door (which I use as the front door) and by the driveway where I can see them as I come home. If the flowers are open, it’s a sign to go outside. By “outside” I mean “Outside” in the John Muirean sense:

I only went out for a walk and finally concluded to stay out till sundown, for going out, I found, was really going in.

–John Muir (John of the Mountains: The Unpublished Journals of John Muir)

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Neerland’s Plantentuin : Afbeeldingen en beschrijvingen van sierplanten voor tuin en kamer by Oudemans, Cornelis Antoon Jan Abraham, 1825-1906; Glijm, C (Biodiversity Heritage Library)

 

p.s. Today, March 31, 2018, is sunny, 51degrees F, with a slight wind chill. The winter aconite have opened and the solitary bee who visited the front-of-the-house patch last Tuesday, is back. (Of course, it could be a different bee, but it seems likely the same bee has come back, as honey bees are known to be repeat visitors.) Here is a video of today’s visit.