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Results tagged “santalaceae”

Dec 6, 2013: Viscum album subsp. abietis and Abies alba

Again, scribed by Taisha. She writes:

Frost and crisp air have greeted me the past few mornings when starting my commute to UBC, two signs in these early days of December that the holidays are approaching. Around the city, empty lots are being turned into temporary sites for Christmas tree sales, lights are being strung up, and wreaths are being hung upon doors. In the spirit of the holidays, I've chosen to write an entry on Viscum album, or European mistletoe! The images of this species are courtesy of stevieiriswattii!@Flickr, who uploaded them to the Botany Photo of the Day Flickr Pool (image 1 | image 2).

Viscum album, a member of the sandalwood family, is a hemi-parasitic evergreen shrub. Hemi-parasites are plants that receive additional nutrients via a haustorial attachment to a host, but are also able to photosynthesize. In the case of mistletoe, their parasitism can lower the host tree's vigour, induce premature mortality, reduce the quality of wood, or induce water stress. As a species, Viscum album is able to infect a large number of host plants. There are five or six subspecies of Viscum album recognized, differing in part by host specificity. For example, Viscum album subsp. abietis (shown today) is a parasite on Abies (fir) species (in today's case, silver fir or Abies alba). Similarly, Viscum album subsp. austriacum parasitizes Pinus (pine) species and rarely Larix (larch) or Picea (spruce) species. Other subspecies parasitize flowering trees or different conifers.

European mistletoe is dioecious and insect-pollinated. The flowers are yellowish to green and inconspicuous. The fleshy white berries ripen through the early winter in Europe, and are bird-dispersed from late winter to spring. Birds do eat the berries, but digestion is not necessary for seed germination. Instead of eating the berries, birds will sometimes disperse the fruit by dropping the berry in flight or while on the tree. The mucilaginous viscin on the outside of the berry allows it to stick to the bark of the tree, where it will eventually germinate and infect (see Kahle-Zuber, D. 2008. Biology and evolution of the European mistletoe (Viscum album). (PDF) Doctoral dissertation, ETH Zurich, No. 18080.

Mistletoe appears extensively in mythology and folklore. To the ancient druids of Britain, mistletoe was a symbol of magical powers and medicinal properties. From Norse legend, Balder (a Norse god and the son of goddess, Frigga), was killed by mistletoe. However, his life was later restored and Frigga, in her joy, said that anyone who passed under mistletoe should receive a kiss. This custom remains today, with kisses being shared under the mistletoe which is commonly used as a Christmas decoration. Where this truly originates, I'm uncertain, although it is known to have been part of Christmas customs since at least the seventeenth century.

If you live in Vancouver, and are looking to decorate for the holidays, the Friends of the Garden are selling hand-made wreaths at the Shop in the Garden until December 23, 2013, or until quantities last!

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.

Jan 19, 2011: Mida salicifolia

Mida salicifolia

...and we're back. Sorry for the gap of a few days, it took us a while to sort out some of the issues in the set-up of the software behind the scenes. I hope it's all resolved now, and the biggest issue of photographs not loading should finally be fixed.

Claire wrote today's entry (thanks again, Claire):

A change from flowers for today. Tony Foster (Tonyfoster@Flickr) from Kaeo, New Zealand, provided this photograph (via the BPotD Flickr Pool) of fruit of the small tree, Mida salicifolia. Much appreciated Tony!

A native to the North Island of New Zealand, Mida salicifolia of the Santalaceae is a small tree found in mixed podocarp forests. The Santalaceae contains 44 genera and 990 species and is broadly distributed throughout temperate and tropical regions of the world.

A hemi-parasite like other members of its family, Mida salicifolia parasitizes through its roots, where it steals some nutrients from its host (often the kauri tree, Agathis australis). However, the species is also capable of photosynthesizing and living independently. A well-known example of another hemi-parasitic species in the family is mistletoe.

Maire taiki is the Māori name for Mida salicifolia, but there are several other species of native New Zealand trees bearing the name maire such as maire hau (Leionema nudum)and maire tawake (Syzgium maire). The Māori Dictionary has additional matches for maire. English common names include New Zealand sandalwood and willow-leaved maire.

The leaves of Mida salicifolia are lance-like (salicifolia = "leaves of a willow") and glossy. Its flowers (see photos on link) are quite diminutive in comparison to the size and appearance of the bright red berries (7-12 x 6-8 mm). Often this species is confused at a glance with small trees of Nestegis species (common names also being maire), but can be easily distinguished by looking at the leaf arrangement: Mida salicifolia has alternate leaves while Nestegis spp. have opposite leaves. Additional photographs of the flowers and vegetative parts of Mida salicifolia (and another member of the family, Korthalsella salicornioides can be found on the University of Auckland, Biological Sciences website: Santalaceae.

The New Zealand Plant Conservation Network (also linked above) states that Mida salicifolia is in decline in areas where browsing occurs from introduced mammal species such as goat, possum, and deer. However, it is relatively widespread, and remains particularly abundant on possum-free islands.

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