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Results tagged “november-04”

Nov 4, 2013: Fallopia convolvulus

Fallopia convolvulus

An entry written by Taisha today:

Today's photo is of Fallopia convolvulus (syn. Polygonum convolvulus), or wild buckwheat. This species exhibits a twining nature and has cordate (heart-shaped) leaves with the presence of an ochrea. Its inflorescence is a short raceme composed of small greenish-pink flowers (with the sepals providing the colour) located either in the axils of leaves or at the end of stems. This photo showing many of these properties was taken by Robert Klips (aka Orthotrichum@Flickr) back in 2007 and was submitted to the Botany Photo of the Day Flickr Pool. Thank you Robert!

This term I'm attending a weed science class. In the lab section, we must be able to identify a number of weedy species and know them by their scientific and common names. When I was studying for the mid-term I was joking with Daniel that he should prepare himself for 40 or so Botany Photo of the Day entries on weeds, being that one good way to learn them is to read and write about them. I didn't end up using this method of study, however I thought it wouldn't hurt to write one entry.

Some people define a weed as being a plant growing where it is not wanted, and more often than not this is the case with wild buckwheat. This species is native to north Africa and much of temperate Europe and Asia, but is naturalized throughout much of the rest of the temperate and subtropical world, particularly where crops are cultivated.

In Biology and Management of Wild Buckwheat (PDF) by Zollinger et al., the authors state that the prevalence of this weed species is due to several factors, including: its binding habit, its resilience despite control strategies, its tolerance to some herbicides and the large number of seeds it produces persisting in the soil. A single plant can produce up to twelve thousand seeds over the course of a growing season. Only three percent of these germinate after the plant reaches maturity, with the remainder residing dormant in the soil for up to five years. Seeds overwintering in the seed bank may germinate after exposure to 3-5 degrees Celsius (37-41 degrees Fahrenheit) for eight weeks. Unfortunately for attempts at controlling the weed, seeds of wild buckwheat are similar in diameter to that of wheat. Seeds often end up being inadvertently planted by the farmer with the intended grain crop.

Nov 4, 2011: Calycanthus floridus

Calycanthus floridus

Carolina-allspice or sweetshrub is native to the eastern United States. Two varieties are recognized by the Flora of North America, with somewhat overlapping distributions: Calycanthus floridus var. floridus which has a range nudging a bit more to the east, and Calycanthus floridus var. glaucus, with a range extending a bit more north and west than var. floridus. Calycanthus floridus var. floridus has pubescent twigs, petioles and leaves (the abaxial surface), with its counterpart lacking these small hairs. I suspect the plant in today's photograph is Calycanthus floridus var. glaucus.

As its name implies, this is a fragrant species. Oils distilled from the flowers are purported to have a "fruity odour reminiscent of ripe apples", while the "bark of this tree [shrub] has a fragrance like cinnamon, for which it is sometimes used as a substitute" (both quotes are from Nigel Groom's The New Perfume Handbook). Flowers on this shrub (to 4m) smell like pineapple or strawberry, leading to two other common names: strawberry-shrub or pineapple-shrub.

Calycanthus floridus is recognized as a Plant of Merit by Missouri Botanical Garden. Additional photographs and writings about this taxon are available from Beautiful Wildlife Garden: Calycanthus floridus.

This photograph is from May of this year in the Asheville Botanical Gardens.


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