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Althytrion β Delicate Killer
Published: 2011-11-23 20:45:29 +0000 UTC; Views: 763; Favourites: 41; Downloads: 0
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Description
You may ask yourself why I call this delicate plant a killer. Well, because it really can be a killer: Orobanche ramosa, or, as some botanists call it, Phelipanche ramosa - common English names are hemp broomrape and branching broomrape. The broomrape completely lacks leaves and chlorophyll, so it is parasitic on other plants, draining nutrients and water from their roots. In former times it often occurred as a pest in agricultural fields and infested crops including tobacco, potato, and tomato, thus causing considerable damage and rural poverty due to massive crop failures.
The English Wikipedia stated that Orobanche ramosa is native to Europe and North Africa and an introduced species in other places (such as North America). In my opinion, however, it is more likely that it happened the other way round, since it prefers American members of the Nightshade family Solanaceae (tobacco, potato, tomato) as host plants. So I guess it was introduced to Europe together with them. Orobanche ramosa also infects Cannabis, as the common German name "HanfwΓΌrger" (="Cannabis slayer" or "Cannabis strangler") suggests. It has become very rare in Germany, however, and almost lost its harmful potential in our region. I have been growing this broomrape for a couple of years now, in a pot together with Oxalis pes-caprae, a South African sorrel, but it does not flower in every year.
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Comments: 52
Wow, what an unusual specimen! Thanks for sharing, Kevin!
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Thank you very much, George!
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Yes, it really is a wolf in sheep's clothing.
Thank you so much, dear Nataly!
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*Prunus vulgaris
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Accurately observed, Katie!
The Orobanchaceae family is in fact related to the Lamiaceae family, where Prunella vulgaris belongs to.
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that was the exact thing I asked myself as I started to read! Unusual bkgd for this plant. If planted in a garden setting would it also harm flowering plants? Guess it's best if kept in a pot! You always keep things interesting w/all the info. 
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It can feed on several other plants, as well, for instance also on species of the Fabaceae family, such as clover and Sweet Pea.
So I better keep it in its pot, and since the sorrel Oxalis pes-caprae is a very vital host, both can grow together.
Thank you very much, Chibi!
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Potted sounds like a very good idea!
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Very interesting. A sort of botanical vampire.
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Yes, indeed - and it's not the only one existing ...
Thank you very much, Eddie!
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Light and dreamlike, such a lovely colour too.
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Thank you very much, dear Jo!
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Thank you very much, Dave!
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Thank you very much, dear Linley!
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Excellent capture! I'm glad you were able to get a shot of it in bloom this year
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Thank you very much, Devi!
Yes, I'm glad, as well - and I hope it'll flower again.
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How interesting! Thanks for the info and to Ratabago & MesmerizedbyNature for added details 
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Oh, broomrape species are native to and wide-spread in North America, as well. The problem is that you cannot see anything of them except for the short time they are in bloom, and then you only have a few days to find them. If you see any flowering plant that (almost) completely lacks chlorophyll (and reminds you of a mushroom, therefore), it probably is a parasitic plant.
Thank you very much, Ruth!
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Delicate indeed. This is the most attractive shot I've seen of this species.
This plant is a pain. Locally it's known as branched broomrape or naked broomrape. It affects a very varied list of host plants including several Fabacea (medicks, vetches),lettuce, canola, members of the Asteraceae, and Solanums. Doesn't look like it's a terribly fussy parasite. It produces up to 40,000 seeds per plant, which remain viable for a decade or so. In South Australia about 5000 sq Km of land have been infested with this stuff despite quarantine measures.
Weeds Australia also says this stuff is native to Northern Africa, Southern Europe, the Middle East, and Western Asia. The US Federal Government list it as a non-native noxious weed. Perhaps the vulnerability of N. American Solanums is just because they haven't yet developed any resistance to this parasite?
Over here branched broomrape dies after flowering. Are you managing to keep the same plant going year after year, or are you replanting it?
I don't think I'll let the local politicians know it's also called "Cannabis slayer". They'd be releasing it into the wild to inconvenience some of the less reputable market gardeners here abouts.
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Thank you very much, Jim, also for this additional information!
I wasn't aware of the fact that is so invasive in Australia, as well.
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The speculation I've heard is that it came in with crop seed. So far it's seen as a major agricultural threat, and not much of a threat to native bush land. But not that much research has been done on it's impact on natives. We've got another Orobanche that's an agricultural pest, the clover broomrape (O. minor), but it causes relatively little damage.
There's also a native broomrape, O. cernua var. australiana, but it's rare and not a nuisance. I've only seen it once, a long time ago.
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Very interesting!
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It's the only native Orobanche. I think it's restricted to parasitising native Senecio species. But some of the weed people include clover, chickpeas, and sunflowers in its host species. I suspect they're confusing it with O. ramosa as they talk about it causing significant crop reduction. That seems vanishingly unlikely for a threatened species.
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I fully agree! In fact, they should be more accurate in identifying these plants, even if Orobanche species are sometimes difficult to distinguish, especially when not flowering.
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That seems very possible!
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Thank you very much, Doug!
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Thank you very much, George!
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That may be legit.
Though on Rhodes, it was very common and parasited on almost everything it seemed.
Subspecies or populations parasitic on tobaco/potato/tomato can have been introduced in such plantations with the hosts, and there it prefers those species.
That could also be the case. ^^
Where it's origainally from it shouldn't be as strict in hosts.
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Yes, they're abundant throughout the Mediterranean region - but Oxalis pes-caprae is a wide-spread species there, as well, in spite of the fact that it clearly is of South African origin, and introduced not before 1800.
Maybe, there originally were two (sub-)species of Orobanche ramosa, one in Eurasia and the other in Central America, which both were rather specialized and not very widespread. Due to the introduction of Solanaceae from the New World, the American species came to Europe, and heavily hybridized with local varieties, thus forming this very vital form we observe today?
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But as orobanche is a parasite, it wouldn't not as fast spread. Or not as often at least, as it needs to find and adapt to hosts. Other plants can spread very fast if the environment is right otherwise, but there is a slight difference in parasites I would say.
Other species of Orobanche does have a hard time surviving (at least in Scandinavia)and are often found in plantations were there is an abundance in host, and there masses of them can be found, maybe with help of a slight adaptaion.
The case with two populations somewhat alike that soon hybridized could be the case, but the idea that there would be two of the same genus that looked alike on different continents is not as possible, especially with specialisation such as parasitism. But some populations of orobanche that hadn't really found specialisation and that were spread throughout their regions would be more possible, I would say. Then there would be fast development if one O. sp was introduced to the other continent. ^^
And I think that introduction has happened both ways, if there were two populations.
The fact remains, Orobanche is a hard genus. XD
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If two related species from different continents, which have a different genome but no hybridization barrier, are brought together, they'll hybridize in many cases, and the hybrids will often show a special vigor due to the heterosis effect. You can see this, for instance, in all the artificial hybrids of Cypripedium species from Asia, America and Europe: many of them are very vigorous and much easier to cultivate than the true species, and have therefore become ideal garden plants.
You're right, the situation for parasitic plants is somewhat different from that of autotrophic species. 
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Firstly, Cypripediums are orchids, a family known for low hybridization barriers and such. But that's not what I'm talking about, I'm just stating that to call them subspecies are not very valid. I see now that I didn't really say what I meant. ^^ I wrote something first and then I changed some, but forgot to change it all... :S
But yes, I am well aware of populations of the same genus that hybridize when contact is made. I tried to state that to call them Orobanche sp. would be more legit.
And I think that when not talking about orchids, it would be the species not very specialised that would hybridize mots efficiently. And one more thing, there are more species that look very much alike O. ramosa in Eurasia. I don't know about American species though. :S
And your last statment, yes. ^^
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Okay, I see what you mean, and agree!
Btw, not only orchids from North America and Eurasia hybridize, but there are also intrageneric hybrids of American and European species in genera of other families, such as Fragaria, Rosa, Vaccinium, Rhododendron, Iris. Since geographic separation is an effective barrier (and makes any further, genetic barrier obsolete), two species from distant regions can easier hybridize, sometimes, than two species that use to grow in similar biotopes, or even side by side.
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But orchids rarely hibridize like that in the wild with their specilasation. But the thing with orchids are that barriers are not often in the actual fertilazation, but in the pollination, and therfore there would not be barriers against hybridisation. Therefore it's a bad example. ^^ In many orchid genuses there simply aren't barriers in fertilazation. ^^
I am well aware. ^^ And it's not very odd, as no barriers have had to be made, as there often are in species closely ralated in the same area, either by fertilazation or specilation in pollination and others.
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Yes, you're right that the pollination is the crucial point in natural hybridization in Orchidaceae - but nevertheless, orchids do heavily hybridize in the wild! For instance, hybrids between certain Orchis species, or between Anacamptis species, or even between Anacamptis and Serapias often occur and can form large hybrid swarms.
In Dactylorhiza, the situation is even more complex, as recent genetical analysis has shown that there are a couple of species with a special development (such as D. viridis, D. sambucina), while D. fuchsii/maculata and D. incarnata (as true species) form a complicated system of intrageneric hybrids that is unbelievably variable in their genom (and habitus) and can more easily adapt to a change of the local ecological situation, therefore. For this aggregat, sometimes the name "D. majalis" is suggested - in a broader sense than before, since it includes many forms that have previously been described as species of their own.
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as a total botany nerd, let me get a word in edgewise!
yes, it is an absolute fact that species from in some cases opposite corners of the world resemble or even can be artificially bred with each other. the fact remains that all plants and living organisms for that matter, have a tendancy to become for any and all reasons, isolated in some way shape or form from other members of their population which results in the imperative process of natural selection of the fittest members and eventual speciation. this phenomonon occurs over surprisingly small distributions even in the same substrate as the parent specie at times. the opposite can be true ocassionally as well, for however unlikely reason. the orchid Liparis viridiflora is absolutely naturally cosmopolitan in distribution, occuring in tropical America, Asia and Africa while remaining for whatever reason the same with little local variation. other thoughts are within entire genuses as well, take Bulbophyllum, Cypripedium, Platanthera, Habenaria, and Vanilla as examples. Calypso bulbosa has four forms from a trans-polar distribution, asian, pacific northwest, eastern seaboard, and central European that differ only slightly. odder yet is the resemblance of members of Chloraea, Gavilea, Codonorchis and Bipinulla, to species in the Caladenia and Diuris alliance over 4000 miles away in Australlia.
the way it goes along is fascinating, the explanation I infer that fits these examples is parts of coevolution in paralell climates, hox gene switches that are dominant and maybe the varrying rates of competition and biodiversity, the catalists for new secies.
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Yes, but those are when in the same area. ^^ I am just stating it was a bad example as there are no barriers in fertilization, so when miskates occur with pollination, there are often fertilized. And yes, that's what I'm talking about. ^^ But as they're specilazed that much, they don't ofen live for more then the first generation. And that is actually what I was talking about. ^^
And I know, Dactylorhiza are impossible. The only cause is that they haven't yet found their niche.
^^
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