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Results tagged “violaceae”

Apr 11, 2014: Isodendrion pyrifolium and Solanum incompletum

Another entry from Taisha, who writes:

Today's images (original 1 | original 2 | original 3) are of two rare and endangered endemic Hawaiin species, Solanum incompletum and Isodendrion pyrifolium. These photos of cultivated specimens were taken by David Eickhoff (aka D.Eickhoff@Flickr) on the Hawaii'in islands in May of 2008. The first photo shows the foliage of both species, while the other two give you a better idea of Solanum incompletum in flower and fruit. Thanks for sharing, David!

Isodendrion pyrifolium, of the Violaceae, is part of a genus of slender, woody shrubs. Isodendrion is from the Greek isos, equal, and dendron, tree, referring to the subequal petals and woody habit of those within the genus (here's a picture showing the flower of the species from Cornell's EES Field Program in Hawai'i). The four known species of Isodendrion are endemic to Hawaii, and are under threat due to urban development, fire, invasive plants, predation, and herbivory. Isodendrion pyrifolium, known as Wahine noho kula, is a branched shrub that was once thought to be extinct, having last been seen in the 1800s. It was rediscovered in North Kona on the island of Hawai'i in the early 1990s. Historically, this species was found on the islands of Ni'ihau, on the slopes of Mount Ka'ala on O'ahu, Moloka'i, Lāna'i, Hawai'I, and reported by Hillebrand in 1888 from Maui.

Solanum incompletum was what caught my eye in the first photograph with its reddish armature on the stems and leaves. This species, known as Pōpolo kū mia or pōpolo, occurs in dry to mesic forest, diverse mesic forest, and subalpine forest. Solanum incompletum is endemic to the islands of Maui, Lāna'i, and Hawai'i, although the book, Manual of the Flowering Plants of Hawai'i (volume 2), states that it also occurs on Moloka'i, Kaua'i. This species was also thought to be extinct for over 50 years. Despite rediscovery, it remains threatened by feral sheep, goats, pigs, alien plants, and fires.

Aug 29, 2011: Viola cuneata

Today's photograph was from the third week of May this past year, from a sidetrip to the Gasquet Darlingtonia Botanical Trail in California (not to be confused with the one near Florence, Oregon). I had hoped to see a particular species of Trillium there, but struck out again. Still, the wedgeleaf violets (cuneate = "like a wedge") were out and in a convenient place to photograph, so I spent some time with them.

Viola cuneata is found only in northwestern California and southwestern Oregon. It is often associated with serpentine soils (a serpentinophyte), but it is not exclusive to these difficult growing environments. Studies have shown that it is able to accumulate high amounts of nickel in its tissues (up to 664 µg/g) without any apparent adverse effects (see Reeves, RD et al. 1983. Accumulation of Nickel and Zinc by Western North American Genera Containing Serpentine-Tolerant Species Am. J. Bot.. 70(9):1297-1303). Other nickel-tolerant species, such as Thlaspi montanum are hyperaccumulators of nickel (>1000 µg/g), and it has been shown that this is effective in producing tissue toxic enough to kill feeding insects (see Boyd, RS and SN Martens. 2004. Nickel Hyperaccumulated by Thlaspi montanum var. montanum Is Acutely Toxic to an Insect Herbivore. Oikos. 70(1):21-25).

Additional photographs of wedgeleaf violet are available from the Oregon Flora Image Project: Viola cuneata and Calphotos: Viola cuneata.

Sep 9, 2010: Viola cano-barbata

Rosulate violets have previously been featured on BPotD (see: Viola atropurpurea), but not in flower. I was reminded of these intriguing plants after attending Alan Tracey's lecture last night on the plants of the central Chilean Andes (via the Alpine Garden Club of British Columbia); Alan has kindly agreed to share these photographs he took at La Parva. For one additional photograph of Viola cano-barbata, see this discussion on the Scottish Rock Garden Club forum. It has a photograph from Philip MacDougall, who traveled with Alan on the trip to Chile.

Little information exists online or in available-to-me print resources about Viola cano-barbata. It doesn't have a common name that I can find, though cano means "hairy" and barbata means "bearded", so perhaps the hair-bearded violet (in reference to the leaves). John Watson briefly described Viola cano-barbata in The Bulletin of the Alpine Garden Society (Vol. 45: 227): "Downy whorls of green leaves suffused pink pile up until ready to emit a ring of white-centred violets of striking velvety black-indigo, peeking cheekily from under the edge."

The range of the species is restricted to high altitudes in Chile and the Mendoza province of Argentina; these particular plants were photographed at above 3350m (11,000ft), I believe. The compressed, flattened habit of rosulate violets helps to maximize sun exposure (in order to make the most of the short growing season) and minimize wind exposure (to reduce water loss). The hairs of Viola cano-barbata also provide a mechanism to reduce water loss by providing an insulating layer of still air around the immediate surfaces of the leaves and (this is speculation) reduce the deleterious effects of intense UV radiation at altitude by diffusing the light. However, Bobby Ward in The Plant Hunter's Garden: The New Explorers and Their Discoveries, notes that the adaptations to intense sunlight have led to the plants to require high light levels. Ward comments that one of the problems with rosulate violets in cultivation at lower elevations is etiolation, where stem growth is extended (and weaker) as the plants attempt to grow toward an area of higher light.

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