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Results tagged “oxalidaceae”

Aug 5, 2014: Oxalis oregana

Oxalis oregana

Here's a photo of Oxalis oregana, or redwood sorrel. I took this photo in May, within the California coast redwood forest of Prairie Creek Redwoods State Park. This was during an ecology field course.

Oxalis oregana, of the Oxalidaceae, is native to coastal British Columbia, Washington, Oregon, and California. This perennial groundcover grows in dense carpets under the shaded canopy of redwood and Douglas-fir forests. Redwood sorrel is a species that prefers shade--photosynthesizing at light levels of 1/200th of full sunlight. When it is too bright, the three heart-shaped leaves fold downward until it is shady again.

Not seen in this photograph are the delicate, pink to white flowers with five petals. This species also contains oxalic acid, leaving the edible leaves with a sour and tangy taste. This hints at the genus name Oxalis coming from the Greek oxys, meaning "sour".

Feb 6, 2014: Oxalis triangularis subsp. papilionacea

Oxalis triangularis subsp. papilionacea

We'll do a bit of a rewrite for yesterday's entry due to the misidentification, but that might not show up until next week. In the meantime, here's the next in the nastic plant movement series by Taisha. She writes:

Today's photo is of Oxalis triangularis subsp. papilionacea or the purpleleaf false shamrock. Another common name is the love plant. This photograph was taken by Anne Elliott (aka annkelliott@Flickr), and shared via the Botany Photo of the Day Flickr Pool. Thanks Anne!

Oxalis triangularis subsp. papilionacea is native to rocky stream banks of Brazil. A recipient of the Royal Horticultural Society's Award of Garden Merit, this attractive taxon with its striking pink flowers and red-burgundy-purple triangular-shaped leaves is often grown as a houseplant in temperate climates.

Purpleleaf false shamrock moves in response to changes in light, i.e., photonasty. When exposed to light, the leaves of Oxalis triangularis subsp. papilionacea fold out and upward. In response to darkness, the leaves will fold down and inward (timelapse video). The light-receptive part of the plant that receives the stimuli in this taxon is in the pulvinis (the section between the leaf and petiole) (see: Kang, JH. et al. 2009. Leaf movement by light condition in Oxalis triangularis. Hort. Environ. Biotechnol. 50(4):371-475).

Mar 25, 2011: Oxalis palmifrons

Oxalis palmifrons

Claire Fadul, BPotD work-study student, is the author of today's entry:

Nhu Nguyen (Xerantheum@Flickr) of Berkeley, California submitted this photo of Oxalis palmifrons, taken in his garden, via the Botany Photo of the Day Flickr Pool. Much appreciated Nhu!

Oxalidaceae is the wood sorrel family, containing mostly annual and perennial herbaceous plants (some shrubs, too). Oxalis has the highest species diversity within the family, with over 90% of the members of this family ascribed to that genus. Of the roughly 700 species in Oxalis, most are distributed in the tropics and subtropics, though some can be found in more temperate regions. Oxalis palmifrons is a native of the arid Karoo region in the Western Cape of South Africa.

Oxalis contains species of ornamental and food value, but the genus also has its "villains", with some species being pesky weeds. Reproduction in Oxalis can vary from bulbils to runners to seeds. Many species have evolved heterostyly, where male and female parts are spaced apart on the flower (height or location) to ensure they are not self-fertilized. The delicate pink flowers of Oxalis palmifrons are shown on the Pacific Bulb Society wiki: Oxalis palmifrons.

Flowers, though, are not what Oxalis palmifrons is known for -- it's the foliage that is of most horticultural interest. The plants tend to form a dense, low cover over the soil during the winter. Their leaves are quite tiny (1cm on average), but can contain up to 20 "fronds" on each leaf, and will fold at night and reopen during the day. Leaves of Oxalis palmifrons are also covered in hairs, which can help reflect the high-intensity sunlight plants experience in the arid Karoo.

Jan 27, 2011: Averrhoa bilimbi

Averrhoa bilimbi

Today's entry was written by Claire:

3Point141@Flickr provided us with this photograph via the BPotD Flickr Pool of the fruit and flowers of Averrhoa bilimbi, a tropical tree belonging to Oxalidaceae (taken in Pinellas Park, Florida). Much appreciated 3Point141!

Oxalidaceae, or the wood sorrels, is a small family of 6 genera and 770 species distributed in temperate to tropical regions. Common to the family, and also visible with the flowers of Averrhoa bilimbi in the photograph, there are five petals and stamens in multiples of five in the whorl.

Averrhoa bilimbi (named after Averroes, a Muslim astronomer and philosopher) is a long-lived tree that produces an edible, refreshing fruit. Some common names of this species are (funnily enough) bilimbi, cucumber tree, and pickle fruit - the latter two attesting to what the fruit resembles. Averrhoa bilimbi is often compared with another popular, cultivated tree in the same genus called Averrhoa carambola, which most people know as starfruit or carambola.

The species likely originated on the Maluku Islands of Indonesia, but varieties are now commonly found throughout southeast Asia and other tropical areas worldwide. It has been cultivated in tropical regions for centuries and has accumulated a swath of local common names: Averrhoa bilimbi nomenclature via Wikipedia.

Averrhoa bilimbi can often reach heights of ten meters or higher. It can be found in gardens for ornamental purposes (as you can see, the flowers are very exotic) but it is typically grown for local production of food. The fruit is quite acidic and cannot always be eaten raw (though it is sometimes a snacking food). Fruits can also be sweet or savoury depending on the cultivated variety. Pickling, cooking, sugaring, currying, and juicing are some ways Averrhoa bilimbi is used in local cuisine.

Ecology resource link (added by Daniel): Frequent BPotD contributor, Eric in S.F., suggested a note regarding a newly-immigrated kudzu-eating bug in the southeast USA. Kudzu (Pueraria lobata), a member of the Fabaceae, is an invasive scourge in southeast USA. One would think that a kudzu-eating insect would be welcome, but it turns out that it also happily feeds on soybean and peanuts (also Fabaceae), causing a potential threat to those industries. Also, residents are concerned that the rather-smelly bugs can cause quite the odour when they congregate in the thousands. Read more via Alabama Cooperative Extension: State's Residents Should Be on Watch for Kudzu Eating Insect.

Apr 15, 2010: Oxalis acetosella

Oxalis acetosella

Lindsay B. wrote today's entry:

Thank you to marcella2@Flickr for submitting today's photo (original image | Botany Photo of the Day Flickr Pool)!

Oxalis acetosella is a cleistogamous perennial herb common throughout most of Europe and parts of Asia. Oxalis acetosella, commonly known as wood sorrel, grows in clonal stands typical of self-pollinating plants. The leaves of wood sorrel are clover-like, and for that reason it is sometimes referred to as a shamrock (though shamrocks also often refer to true clovers, Trifolium spp.) and given as a gift on St. Patrick's Day.

Wood sorrel, like spinach and broccoli, contains oxalic acid, a common ingredient in cleaning products and rustproofing treatments. When ingested, oxalic acid interferes with food digestion and the absorption of some trace minerals--part of what makes it such an effective cleaning agent. The Latin "oxalis" is derived from the Greek "oxus", or sour, which is indicative of its taste. However, research has indicated that the level of oxalic acid present in wood sorrel (as well as spinach and broccoli) is not harmful to humans in small amounts.


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