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CLICK TO RETURN TO PAGE 2 OF LIST OF PAPERS CLICK TO RETURN TO PAGE 1 OF LIST OF PAPERS CLICK TO RETURN TO PAGE 3 OF LIST OF PAPERS 68. Is You Is, or Is You Ain’t?, PUP TALK (Saddleback Valley Bromeliad Society), 17(2), p. 5-8, February, 2010 By Jerry and Terry Krulik The question of, What is a species?, is of prime importance to professional botanists. Hobbyists, however, are even more picky than botanists. A botanist may look at one plant from a large distribution area, notice that the ones at the eastern, western, southern, and northern ends look quite different, but then say that they are ‘only’ one species since they are all reproductively connected. The normal hobbyist will look at the same plants, label one as ‘typical’ and then proceed to give names to every form that looks both different and interesting. Beginning bromeliad growers are very perplexed by this, and are always asking more experienced growers, Are you sure that this is species so-and-so? It doesn’t look the photo in the one book that I have. They get even more perplexed when it comes to hybrids and varieties. I have seen experienced hobbyists hotly debating whether a plant was, say, Red Comet or Reddish Comet or maybe a hybrid between the two. With the experience of years and a bit of memory loss, I look on these hot- headed discussions as pretty much useless. Let me explain my reasoning. Plants in the field are assumed to be species, unless further study shows them to be hybrids. Hybrids can become species, if they become ‘stabilized’. This means that the hybrids, and maybe the parents, cross-breed together until there is a population of plants with sufficiently integrated genes that when they mate, they all look pretty much alike. Contrast this to the F1 (first generation) and F2 (second generation) progeny. F1 plants are the original hybrid. They mostly look intermediate between the two parents, though often some of the genes of one parent are suppressed. All the seeds produced in one mating and one seed pod between two plants, is called a grex. Orchid growers know that while the plants of one grex are very similar, the different pollen grains and ovules combine together slightly differently. Once they flower, the very best of the grex are sometimes given varietal names. F2 plants are the products of mating two F1 plants. The parents may be from one grex, or from different grexes of the same species crossings. Now the original genes can segregate, or line up, and increase or decrease any given trait such as size, flower color, branching, etc. This produces your typical hybrid swarm. Selected plants of both F1 and F2 crosses are often extensively propagated in captivity, and sold under many trivial names. There is NO way to tell these hybrids apart once you have many of them, unless you have a very good DNA lab and data references. This is why locality data is important to taxonomists and specialists. All plants in cultivation are suspect; they may have been a hybrid five generations back, and then subjected to further selection, until they may look like the original wild plant, even if they are not. Bromeliad growers are fascinated by the color schemes of their plants. Most plants are pretty punk, having some basic shade of green over their whole body. Bromeliad species often are brightly colored, with lines, blotches, points, stripes, and blobs, of many different colors. Some plants may be red, white, green, black, and so on, in just one leaf. These colors are intrinsic in the cells themselves. However, a blob or a line of one color, can arise from a single cell or a group of cells. Bromeliads are somewhat unusual for cultivated plants, in that they are what I think of, as perennial annuals, since new plants have to be propagated but not from seeds in most cases. Once they flower, in the majority of species the adults will die. Most of them will not die immediately, but will initiate new shoots from the parent stem. This type of natural cloning, is not quite what most people think of as cloning (like identical twins). Apple trees are typical in that they are cloned by rooting or grafting a stem, all the cells of which are substantially identical. Bromeliad clones arise from a small patch of meristem which becomes a new shoot. This has some major consequences when the parent plant has distinctly different colors and distributions of tissue. (Sanseverias and Haworthias are common plants which follow the same pattern as Bromeliads). Let’s look at a popular plant, Aechmea orlandiana, and some of the consequences of natural cloning. The parent plant, and a number of named varieties, are easily available. Bird Rock lists several varieties: Rainbow, Snowflake, Ensign, and Black Bands, in addition to the putative species (1). This is the parent species, a colorful clone from Bird Rock. (1) But here is another photo of a different plant of the parent species, from Houston. (2) Now let us look at the popular variety ‘Ensign’, which Terry bought from Bird Rock some years ago. Terry has had considerable success with this plant and we have many propagules of the original beautiful plant. However, many of the propagules do not look particularly like the parent. Random clusters of meristem tissue may or may not have the original red, green, and white patterned cell arrangement. Since we do not cut off and destroy shoots which look different than the parent, we have many new types of plants. Here is a photo of some of Terry’s plants. 1. Variety Ensign. Most offsets look like this one. 2. Variety that looks more like the parent, A. orlandiana, but is partially variegated, like the plant pictured in the BSI link, labeled A. orlandiana variegated (3). It just has a less visible red component than #1. 3. Variety that is a total variegate, with no coloring matter. 4. Variety that looks totally different, somewhat like a mix of 2 and 3. All of these ‘varieties’ are just random pieces of A. orlandiana tissue. Since A. orlandiana can produce Variety Ensign, which then back-produces the parent, plus more Ensign, plus many other varieties, you can see why a botanist would just call these A. orlandiana. And you can see why hobbyists like to use trivial variety names. Remember one crucial point. None of these varieties were produced by sexual selection. Each one has the total complement of A.orlandiana genes. They are just expressed, pigment-wise, slightly differently in each offset. Thus every plant is genetically 100% A. orlandiana. They are not species, since species have different genetic codes. They are not sub-species, because those also have different genetic codes, with just less of a difference than between species. You can call them forms or varieties, not scientifically valid as taxonomic descriptions, but useful as botanical bookmarks. . So if anyone argues about microvarieties, just ask, Is You Is, or Is You Ain’t, (4) a species? Let them come up with the answers. References: 1. www.birdrocktropicals.com 2. Houston Bromeliad Society, http://www.bromeliadsocietyhouston. org/html/gallery/pages/Aechmea-orlandiana_jpg.htm 3. Bromeliad Society International, http://fcbs.org/pictures.htm 4. Remember the old song, Is You Is, Or Is You Ain’t, My Baby? |
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