Yucca nana

Beautiful, Martin.  The flower spike is just as wonderful as the flowers themselves.  Maybe more!

Someday, I hope my Yucca nana  looks that good...

Martin very nice plant and photo. Yuccas in bloom are very dramatic and defiantly steal the show!
But they don't stop there. They give some of the best year round drama to the dry garden when the early morning or late afternoon sunlight reflects off the leaf fillaments. They seem to be on fire.

Here is my Yucca nana.

It does have several heads but has never flowered. I think the growing tip got damaged in it's youth.

Martin do you hand pollinate your Yucca flowers? I know I read and article, some time ago, on the process.  I have been toying with the idea of doing it myself. I of course have the collection of yuccas but not the collection of moths I would need to pollinate them all.

I have one Yucca (filamentosa maybe) in the garden but it doesn't grow well. Maybe Y nana had been a better doer? Seems to be a terrific plant!

Here it is again.

Bob

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I have grown Y. harrimaniae (and sold plants on the nursery) for quite a few years and it seems quite variable. 

Is that an understatement!  I imagine that botanists consider Yucca nana to be a small form of harrimaniae. I have several "harrimaniae" in the garden here, and none looks like another, except that they're obviously yuccas.
I got fed up with the treatments of Yucca in the various floras and sprang for Hochstaetter's non-cheap yucca books. They seem more reasonable to me.

Part of an unfinished drawing of Y. harrimaniae, attached.

Bob

Bob, your Yucca nana is especially fantastic!

Every twirl of a fiber is a piece of art. :o

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Every twirl of a fiber is a piece of art. 

I did that myself, of course, using a yucca-twirler.

According to Hochstaetter (who described it), it differs from Y. harrimaniae by having leaves less than 20cm long, a "shorter inflorescence", and pure white flowers.
That's probably not enough of a distinction for some botanists.

Bob

Nold wrote:

I did that myself, of course, using a yucca-twirler.

Bob

:D Where can I get one of those yucca-twirlers?  ;)(good one)

Another example of Cindy's magnificent artwork, Bob?  ... but what a legacy!

Yes, sorry, I forgot to mention that. She was working on a large drawing for an exhibit at RBG Kew.

Bob

As far as I can tell, the only place where Yucca nana is accepted is in Hochstaetter's books. On the other hand, the only treatment of Yucca that I know that is the result of going out into the wild and looking at as many yuccas as possible, is also by Hochstaetter.
I noticed he was dismissed as a "hobbyist" in some publications, but who else has done as much field work? Especially in such as messy genus as Yucca, I would think that field work outweighed studying herbarium specimens in every respect. (I could be wrong.)

If you look at treatments of Yucca in various floras you will find almost no agreement at all as to the distribution of a number of species, not to mention reports that species grow in places where, in fact, they do not grow.

Bob

Nold wrote:

If you look at treatments of Yucca in various floras you will find almost no agreement at all as to the distribution of a number of species, not to mention reports that species grow in places where, in fact, they do not grow.
Bob

I don't see this situation changing for the better. Field botanists and regional herbariums are finding it hard to get funding for projects and operations.The lion's share of current funding is being funneled into the genetic profiling of the plant kingdom. How is a geneticist sitting in an office even aware of what a species is supposed to look like, let alone be able to say were it's habitat begins and ends. How is he going to be able to tell the subtle differences, between varieties of a species, since they only test a very small portion of a specie's, genetic code in the first place? There seems to a push to make every species into a bar code, that you can scan with a hand held tricorder and positively identify. I don't see that happening any time in the foreseeable future. There are way too many plant species to begin dealing with. :rolleyes: There are many university botany programs that have dropped their taxonomy classes in favor of genetic research. Were will the future taxonomists come from? Who will update the treatments and back them up with vouchered specimens?  With the climate changes predicted in the future, who is going to do the field research required to monitor the changes?
Lots of questions unanswered , but money talks!!

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I don't see this situation changing for the better.

Cactus are a complete mess. Some species have 25 synonyms.
I don't find any treatment that recognizes Opuntia debreczyi (nor, for that matter, O. rhodantha). You probably couldn't find two botanists who even agree on what constitutes a species, let alone whether or not a specimen represents a species.

It wouldn't really matter except for the very real possibility of buying the same plant over and over again, but with a different name each time.

Bob

Nold wrote:

Cactus are a complete mess. Some species have 25 synonyms.
I don't find any treatment that recognizes Opuntia debreczyi (nor, for that matter, O. rhodantha). You probably couldn't find two botanists who even agree on what constitutes a species, let alone whether or not a specimen represents a species.

I agree that cactus are a mess and Opuntias the worst of the lot!! Yes there is a lot of doubt out there about the validity of debreczyi. Rhodantha as a group needs study, to see if it has valid varietal standing.

Here in a somewhat lengthy write up on the "species concept" that I found a good read.

The concept of a species is a surprisingly difficult concept, perhaps because it is so basic to our understanding of the world. After all, virtually the first question most people ask is "what is it?"

That "what is it" concept is designed to group things into similar and different categories. Those categories can vary enormously. Sometimes they are more specific than a "species". For example, a Golden Delicious apple is different from a Macintosh apple is different from a Winesap. Sometimes less specific. "hardwood" vs. "softwood".

In modern biology, we not only have the concept "within group" vs. "different group", but we have added the concept first of grouping at different levels "Cactus" vs. "Opuntia" vs. "Opuntia fragilis" vs. "Opuntia fragilis. var. brachyarthra" , and we have added the concept of reproductive isolation at the species level. In other words, we want to believe that species X every individual within the species is capable of producing offspring with any other individual, at least of a different gender, and that species X individuals cannot produce offspring with members of another species. And, of course, this concept works reasonably well for many groups. Robins don't have babies with scarlet tanagers, and with only a few exceptions (chihuahuas and St. Bernards) individuals within a species can produce offspring with another individual in that species.

However, even though we've added that concept, in reality it is neither obeyed by many "species", nor is it measured by biologists attempting to define species. The oak tree in front of my house will happily try to have sex with almost anything, including my nose. Imagine, for example, if I tried to publish an article "Opuntia fragilis and Opuntia polyacantha naturally hybridize, and have numerous offspring in some parts of the world. Therefore, they should be lumped into one species..." And the inverse of the concept isn't even true, that within a species individuals should be capable of producing offspring. Opuntia fragilis, for example, won't let pollen from genetically similar individuals fertilize its eggs. Which leads to a real absurdity: two clones of Opuntia fragilis should be two different species???

Well, I'm digressing. But my first point is that the very concept of a "species" is a messy one, and those of us interested in cactus should know that the cacti are a great example of this messiness. Everyone should keep in mind that the very concept of a "species" is fragile in this group. Call it reticulate evolution, hybridization, morphological complexity ...

Second. We define species based on appearance (and now increasingly on rather arbitrary concepts of DNA).

Third. Without a touchstone of some external measurable reality to help us determine species, we are always going to have disagreements. Lumpers will lump, splitters will split. We can look for guidance in things like morphological variation, DNA variation, etc., but we are always going to hear "looks like ..." or "could be a hybrid" ...

Therefore. The very concept of a "correct" species nomenclature is rather arbitrary. I commend you for you desire to be accurate and up-to-date, and indeed I do the very same thing in the herbarium I curate for example. But think of the very concept of what some of your species of interest are ... think of that as a sort of extended conversation. Benson, sitting in the corner, remarks that it is X. Anderson disagrees. Dave Ferguson tells a long story about the last time he saw it, and thinks it is Z. This is why one of the most important pieces of a scientific name isn't the name at all, but the authorities at the end of the name. So when you see Opuntia fragilis (Nutt.) Haw. that is a sort of scientific shorthand saying "the group of plants that Nuttall described first, and called Cactus fragilis. Then later Haworth decided they really belong in a different genus, and moved them to Opuntia fragilis.

So. Enjoy your cactus. Keep track of who they are and where they are from. Love them (maybe not giving them hugs though). And remember that all of those names will persist as long as we keep records, so Cactus fragilis Nuttall and Opuntia fragilis (Nutt.) Haw. are both ways of referring to the same kind of plant. And remember that a species, and a species name, is a uniquely human concept. My Opuntia fragilis is trying hard to live and reproduce, and it doesn't care what species it is.

Well, I've rambled on far too long. Can you tell my students get really hung up on the species concept? And that I've been teaching long enough to get notices that I'm eligible to retire???

Dr. Eric Ribbens
Biology
Western Illinois University
Macomb, IL 61455

Cronquist was more succinct. "The smallest groups that are consistently and persistently distinct, and distinguishable by ordinary means."
Backeberg is said to have described a species from a moving train. (He was on the train.)
If you get seeds of Echinocereus triglochidiatus var. inermis, which is listed as an Endangered Species, you will get spineless plants, some with a few spines, and some indistinguishable from regular "trigs".
As you can see. (Sorry, leafage of Asphodeline damascena in the way.)

Bob

I like the idea of yuccas in pots, too. That way you could move them to weed around them.

Here, you can get plants like that, imported from Texas. They're removed from the wild, growing on private land.
Of course there is a lot of controversy around this, but if you want a 3m tall Yucca faxoniana, you can get one.
Moving it, and digging the hole, are different stories.
Bob

Here are a few photos of Yucca harrimaniae var. gilbertiana in bloom last summer.

Beautiful plant John, the flower spike looks extra plump and showy emerging from the small leaf base.

I think I have to try more Yuccas! I do not know where to plant them though - but I've got an idea ;)
John and DesertZone (Aaron?) you both have inspired me with your pictures ;D
Martin, those I got from you do well so far but I have them potted up and in a coldhouse till I am ready to try them outside ;)

Regarding the question of species:

Specimens are real entities, populations are real but species are artificial constrictions. You can never define a species to cover all kind of cases you'll find in nature. And definitions that hold in the wild will often fall apart when organisms are brought together in for example a garden. However, the concept of species is like all other taxa, a necessity to tally organisms and it also tells us about kinship.

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I have made the combination  flaccida x nana myself and hope for something interesting. 

What about species like Y. pallida or rupicola? Both are hardy here, and though they will grow dry, they do come from wet climates (eastern and central Texas) and will take quite a bit of water.
I would think that hesperaloes (at least parviflora) would do well, too.

Bob

Martin, please tell me when you have anything to trade ;)

Bob, although eastern Texas is wet it also is warmer in summer than any place in Norway (or Denmark)! Summer heat is an important factor too.

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(Does Hesperaloe flower annually in the wild?). 

I don't know. It's not a desert plant by any means. Say 100cm rain a year in the wild. Why it's completely hardy in Denver, I don't know. I imagine that the reason for its drought tolerance has something to do with evolution in the past; it doesn't flower here unless it gets quite a bit of rain (or irrigation) in spring.
A couple of other species, like H. campanulata, have overwintered here (I killed it by moving it around the garden too much) and H. funifera. There's a large plant of the latter at DBG, in a more or less protected location, but here, it turned to mush at 1 degree C warmer than it is right now. (-17C) Uh oh. There's another plant of funifera in the garden, covered with snow. Maybe it will be okay ....

Bob

No plant in my garden will experience that (I hope)! The coldest in my time here (>25 years) is a few days of -16C, even last year which was extremely cold. Today we had +3C and sleet. Now it is +1 and you can fill what covers the ground in a glass and call it slush ;) With some colour added it looks great :o

However, my personal low record is -35C in Northern Norway.

100cm precipitation is more than they get in Oslo and more than I get at my summerhouse I think but much less than I get here.

After reading about it on Alpine-L, possibly, or perhaps in one of Bob's books, I managed to germinate a few Yucca harrimaniae from last year's NARGS Seedex. I hope to see some get to flowering size - how long would it take? I wonder how big they'll get and whether I may have to site them very carefully to avoid those sharp leaves! Weeding will definitely be an issue those I think the Puya we have growing in another part of the rock garden would be worse - it has barbs facing downwards and upwards along the leaf edge so you're caught anyway you try to get in close!
cheers
fermi

cohan wrote:

Good luck with that one, Fermi, sounds nice.. there has also been talk about it on TooColdForCactus yahoo group, and I think Alplains has offered it..

Here's a pic of it as it is at present! I have a long way to go I think!

cheers
fermi