[ Lost in the Landscape ]

fun with hybrids

There are over a quar­ter mil­lion plant species known to biol­ogy. Of those more than 5,000 can be found in Cal­i­for­nia, and 1,500 in San Diego County alone. With so many amaz­ing plant species out there I still find myself being inter­est­ing in hybrids between the pure species.

My last post was on Sar­race­nia, the North Amer­i­can pitcher plants. The genus appears to be fairly new to the world in evo­lu­tion­ary terms, and all the species in the genus will hybridize eas­ily with any of the oth­ers. And all these hybrids will con­tinue to inter­breed with the par­ent species or other hybrids. When you find a bog with two or more species in it, chances are good that you’ll find inter­me­di­ate plants with traits of all the species present in that location.

This dri­ves biol­o­gists crazy. Find­ing a plant that’s a pure species can be a major headache when the plants are out there, frol­ick­ing in the mud. But evo­lu­tion­ary biol­ogy acknowl­edges that hybrids can intro­duce new genes into a plant’s gene pool so that they might be bet­ter equipped to with­stand some stres­sors that a pure species might not.

In addi­tion to pos­si­ble evo­lu­tion­ary advan­tages, a hybrid plant found in nature can be a really cool-looking mon­grel. And human-created hybrids that have been selected for spe­cific traits over gen­er­a­tions can begin to take a species or genus in direc­tions nature would never have imagined.

Here on the left is the Sar­race­nia hybrid Judith Hin­dle. I first encoun­tered mass tissue-cultured num­bers of it in the flower aisle at Trader Joe’s a cou­ple years ago. It’s a pretty great-looking plant by itself, but imag­ine a whole store dis­play of it. This human cre­ated selec­tion derives from three species, and its pedi­gree can be notated: ((Sar­race­nia pur­purea x S. flava) x S. leu­co­phylla) x ((S. pur­purea x S. flava) x S. leu­co­phylla).

Doing the math, you an see that it’s one-fourth S. pur­purea, this species. (My photo here isn’t the exact par­ent, just one gen­eral exam­ple of what this vari­able species can look like. Sev­eral tax­on­o­mists have decided that this plant I’ve shown you, S. pur­purea var. burkii, is actu­ally a new species, S. rosea, but it looks quite sim­i­lar and you can get the gen­eral idea…)

Another quar­ter of the ances­try comes from S. flava. (You might rec­og­nize this same photo from my last post. Once again this is just a rough esti­ma­tion of what the par­ent looked like. It’s actual great-grandparents were S. flava var. rugelli, a plant with pure green pitch­ers with a red patch in the throat.)

And the final two quar­ters of its ances­try comes from the gor­geous S. leu­co­phylla, the white-topped pitcher plant. I find myself com­par­ing the hybrid with the par­ents, try­ing to see the char­ac­ter­is­tics that came through in the final hybrid. Clearly S. leu­co­phylla has the most influ­ence in this cross.

Here’s another com­mon sar­race­nia, S. Dixie Lace. Larry Mel­lichamp, its breeder, isn’t 100% cer­tain of its parent­age, but he esti­mates it to be: (S. leu­co­phylla x S. rubra) x (S. psittacina x S. pur­purea). It shares two par­ents with Judith Hin­dle above, but intro­duces two new species into the mix.

The pres­ence of this ances­tor, S. rubra, is sub­tle, and is prob­a­bly most man­i­fested in the some­what upright-growing pitch­ers and the robust growth habit. (Once again, the plant I’ve shown is only a close approx­i­ma­tion of the S. rubra var. wher­ryi that was used for the actual cross. And yet again, this lat­ter species has been clas­si­fied as a sep­a­rate species by some taxonomists.)

The final ances­tor is S. psittacina, a plant that’s prac­ti­cally impos­si­ble to hide the pres­ence of in any hybrid. The lean­ing growth habit and pat­tern­ing of the pitch­ers takes sev­eral gen­er­a­tions to fade into the background.

Hybrids can hap­pen any­where. In the irri­gated part of my gar­den I have a few sage species from Europe and the Amer­i­cas. These are the leaves of Salvia sagit­tata, the arrow-leaved sage, a plant from Ecuador.

Next to it I noticed a young plant which at first I thought was a seedling of the of its neigh­bor. It has the same light green col­oration and coarse leaf tex­ture as does S. sagit­tata. When I started look­ing closer at the leaves, how­ever, some­thing seemed a lit­tle off. Instead of the dis­tinct arrow shape, the leaves are closer to oval. Seedlings some­times take a while to develop their mature char­ac­ter­is­tics, but I started think­ing that it might be a hybrid of S. sagit­tata with one of the other sages nearby.

Three feet away is S. nemorosa. It also has coarse-textured leaves, but they’re smaller, darker green and rounder (prob­a­bly “lin­ear” to “oblong” with a “cor­date” leaf base, accord­ing to the leaf mor­phol­ogy charts).

And about six feet away are sev­eral plants of the pop­u­lar ‘Hot Lips’ cul­ti­var of S. micro­phylla, a species from Texas into Mex­ico. Its leaves are smooth, much smaller, darker green and also more rounded. (I guess I’d call it an “ovate” leaf form with an “obtuse” leaf tip.)

Who do you think might be the father? I’m lean­ing towards S. nemorosa.

The seedling sage found a clear­ing in the mid­dle of a lit­tle walk­way to ger­mi­nate. I’ll let the seedling bloom to see if it’s interesting–or if it’s even a hybrid at all. See­ing the flow­ers should help me bet­ter guess what its par­ents might be. If it’s worth keep­ing I’ll trans­plant it out of harm’s way. If it’s not, I’ll treat it as any other unwanted gar­den col­o­nizer. What­ever the case, it’ll be an inter­est­ing lit­tle experiment.

Topic for a future post: What’s bad about hybrids?

October 27 2009 | Categories: gardening • my garden | Tags: hybrids • sages • Salvia microphylla 'Hot Lips' • Salvia nemorosa • Salvia sagittata • sarracenia • Sarracenia flava • Sarracenia leucophylla • Sarracenia psittacina • Sarracenia purpurea • Sarracenia rubra | 4 Comments »

sarracenia: an appreciation

So many inter­est­ing plants, so lit­tle time and space to grow them. My cur­rent plant obses­sion is the Amer­i­can pitcher plant genus, Sar­race­nia. I’m not alone in my obses­sion. Brooks Gar­cia even has a firm ded­i­cated to the genus which bears the name Sar­race­nia Obsessed. It’s hard to explain what causes a per­sonal obses­sion but let me try.

The plants of this genus of eight to eleven species all have evolved mod­i­fied leaves that form tubes that attract and cap­ture prey. A fly or an ant and goes for the nec­tar that the plant offers at the tip of the pitcher, and every few of the unfor­tu­nates slips on the slip­pery sur­face and is directed down far­ther into the tube by downward-pointing hairs on the inside of the leaf. Many of the species have a tube filled with diges­tive enzymes that await any crea­ture that makes it to the bot­tom of the tube. The insect even­tu­ally drowns, and is digested by the plant. Dinner.

Evo­lu­tion­ary biol­ogy has devised a num­ber of unpleas­ant ways its crea­tures can meet their ends. Being lured into a nectar-bated trap, then directed by needle-sharp hairs towards a nasty fluid that will start to eat you while you’re still a lit­tle bit alive sounds like one of the more grue­some exits to make. (I’ll never com­plain about another gru­el­ing din­ner party again…)

There are peo­ple who grow these plants where all this car­niv­o­rous unpleas­ant­ness is the main attrac­tion. A lot of these enthu­si­asts are men. Are car­niv­o­rous plants a guy-thing? All this eat-or-be-eaten machismo, Rambo non­sense, I won­der? But I guess I’m a lit­tle defec­tive as a guy—I love to cook and I watch Project Run­way for godsakes—and what really attracts me to these is how seri­ously gor­geous and inter­est­ing these plants are.

Take the case of the yel­low pitcher plant, Sar­race­nia flava. This species fea­tures an extended upright tube (back to that guy thing again, sorry) that’s capped by an attrac­tive lid that hov­ers over the open­ing. These plants live in bogs in lands of many rains, so the lid helps keep rain­wa­ter from dilut­ing the nasty fluid inside the tube. The basic struc­ture car­ries from one form of the species to the other, but sub­tle vari­a­tions in shape and extreme ones in col­oration could keep a col­lec­tor occu­pied for decades.

In my lit­tle col­lec­tion I have sev­eral of the col­ored vari­a­tions that have been described. The pitch­ers look best in the spring and are a lit­tle ragged this time of year. But you can get a basic idea of some of the dif­fer­ences between plants of this species.

Sar­race­nia flava var. max­ima sits at one end of the spec­trum, color-wise. The leaves are all a clean green­ish yel­low color—leaf color—with the only pig­ment being lit­tle patches of red­dish col­oration at the grow­ing point of the rhizome.

S. flava var. flava takes the basic pitcher back­ground color of var. max­ima and adds some strip­ing to the leaves. This is a ver­sion of this vari­ety with an extra-wide maw.

S. flava var. cuprea is also called the “cop­per top” vari­ety. The back of the lid can have a light bronze to dark choco­late col­oration. Some­times the color stays for the life of the pitcher, some­times it fades to green. In pro­longed full-sun con­di­tions this plant can have a won­der­ful dark choco­late top, plus some of the heavy vein­ing you’d find in some of the more heav­ily col­ored varieties.

Beyond these, there’s a var. rugelli, which has all-green col­oration accented with a maroon bloth in the throat, var. rubri­corpa, the “red tube” which has a red body topped with a veined hood, and var. atrop­ur­purea, which has such a heavy suf­fu­sion of red that the entire tube looks that color.

And that’s only one species. There are seven to ten oth­ers, depend­ing on the tax­on­o­mist you’re talk­ing to, with each of the oth­ers pre­sent­ing their own inter­est­ing vari­a­tions on the bug-eating pitcher theme. And all of these species can inter­breed, lead­ing to huge num­bers of hybrids. Check out all the Sar­race­nia pho­tos of species and hybrids at The Car­niv­o­rous Plant Photo Finder. You may end up spend­ing hours at this one site alone and never find a way out of this obsession.

October 25 2009 | Categories: gardening • my garden • plant profiles | Tags: carnivorous plants • pitcher plants • sarracenia • Sarracenia flava | 5 Comments »