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Results tagged “parasitic”

Nov 27, 2012: Pyrularia pubera

Pyrularia pubera

Our spring visit to the North Carolina Arboretum was rewarding, as the institution has a number of delightful areas (not the least of which was an opportunity to visit their research greenhouses). The visit started with a walk through some of the surrounding native forest, which included this shrub. Not particularly showy, I don't think too many people on the trip photographed it, but decided to (it had a label!). I'm glad I did, as it turns out to have some interesting botanical qualities--like the comparison that can be made between it and cobra venom.

There is an exceptional fact sheet about this species written by Dr. Kim Coder for the University of Georgia's Warnell School of Forestry and Natural Resources: Pyrularia pubera (PDF). Much of the information in today's entry is summarized from that work, but if you get interested in the species, I recommend you read his original text.

Pyrularia pubera has several common names; the ones you are likely to find online are buffalo-nut, elk-nut or oil nut. Dr. Coder has listed a few additional ones, including crazy nut and mother-in-law nut. The fruit outwardly resembles a small pear (hence Pyrularia--a small pear (Pyrus)), but the internal development in the fruit of a single pit classifies the fruit as a drupe, much like a cherry or plum. Safe, or at least tolerated, for ingestion by many animals, the fruit is triply poisonous or toxic to humans. Acrid oils in the fruit may cause mouth irritation while calcium oxalate crystals are known to numb tissue (and in high doses, cause death). As for the third, I'll quote from Dr. Coder's report:

"A unique component of Pyrularia pubera is the presence of five different animal-like toxins in its tissues, especially concentrated in the fruit. The shrub contains purothionin, viscotoxin, phoratoxin, crambim, and thionin. A number of these toxins are shared with other sandalwood family members like the mistletoes. Thionin is a small protein which has been proven to be hemolytic (blood), cytotoxic (cells), and neurotoxic (nerves). Thionin attacks membranes in humans (causing them to be leaky) and red blood cells (destroying them.) Thionin can attack heart muscles. It shares the same form of damage and the same binding site within animal cells as does cobra venom, even though it is not similar chemically."

A small shrub growing to 4.5m (15 ft.) tall, Pyrularia pubera is native to dry and moist Appalachian forests from Pennsylvania to Georgia and Alabama. Like all members of the Santalaceae, or sandalwood family, it is a hemiparasitic species (someone correct me if I'm wrong). Pyrularia pubera is a generalist when it comes to parasitism, known to parasitize over 60 species from 50 genera and 31 families, including both woody and herbaceous taxa. Interestingly, one plant of Pyrularia pubera will parasitize another individual of its species, but somehow avoids parasitizing itself.

Feb 5, 2012: Triphysaria eriantha

Triphysaria eriantha

Another member of the broomrape family today, Triphysaria eriantha is known commonly as Johnnytuck or butter and eggs. These annual plants can be found throughout most of California and parts of southwest Oregon. Calphotos has additional images, including photographs of the plants in habitat: Triphysaria eriantha.

Feb 4, 2012: Castilleja coccinea

It is likely this is the first member of the Orobanchaceae that I ever knowingly encountered--a small patch of scarlet Indian paintbrush grew on the edge of some gravel pits about 10km from my childhood home. This species is perennial, so that patch is possibly still there if someone hasn't torn up the rocky soil with an ATV or the like. I do remember being taken out by my parents specifically to see that patch on one or two occasions.

Castilleja has somewhere in the neighbourhood of 160-200 species, and almost all of these are in western North America. Castilleja coccinea is one of the exceptions, as it is broadly distributed across eastern North America. These plants, with their scarlet-red bracts, were photographed in early May.

Feb 3, 2012: Orobanche corymbosa

Orobanche corymbosa

Over the next few days, I'll be sharing some photographs from Thursday evening's presentation on Orobanchaceae (the broomrape family). I've been hearing a few comments that even if a long write-up isn't possible, simply sharing an image is okay, so let's try that.

Orobanche corymbosa or flat-top broomrape, is native to western North America (including British Columbia), where it is frequently a parasite on members of the Asteraceae or sunflower family. In particular, these achlorophyllous plants often grow in association with big sagebrush (Artemisia tridentata).


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