Friday Fabulous Foliage

This was a very busy weekend, it being the day selected to celebrate the annual making of the fish soup.  The ingredients for the entire feast are a bit wide spread so it took some time to locate and purchase everything.  Somehow in the middle of this TPP had not time for blogging, but as a special treat, TPP will use some images sent along from his old friend Dr. Chips.  The images show a large species (no idea which one, it could be one of several or even a hybrid) of the tropical pitcher plant in the genus Nepenthes (neh-pin-theez).  It is a carnivorous plant that uses a pitfall type of trap and then digests drowned prey for the nutrients thus released, primarily nitrogen.  The trap may emit an odor or use a colorful attractant, in this case a nice glossy red rim that might promise a reward within, but the slick footing within and downward pointing hairs prevent escape, and the trap is partially filled with water, so eventually the prey falls in.  Dr. Chips thought that this red rim should qualify these modified leaves for mention in FFF and as is usually the case, he is correct.  Interestingly in the middle image you can observe the tendril like tips of young leaves; the very tip will grow into a new trap.  The curly cue helps orient the trap to hang in an upright orientation.  Quite fascinating bit of tubular development.  So thanks, Dr. C!

Plant poaching

It always sounds a bit weird, but plant poaching does occur. The plants have to be sufficiently rare and desireable to be worth the effort. Things like the ghost orchid of the Everglades and the Venus fly-trap. Venus fly-traps only grow in boggy places near the Carolina coastal area of Wilmington. TPP saw some in Green Swamp, and this report makes it sound like they are none too safe from poaching even though the area is protected from development. Plants that only live in relatively small locales and in fairly restrictive habitats are always the most threatened in the wild. Whenever you consider buying such plants, do give a thought about whether or not the plants were grown ethically and not poached. TPP often asks native plant purveyors where they got their stock. But what a shame if cool little plants like this become extinct in the wild. Too bad there aren't any really big carnivorous plants, think little shop of horrors, that you could feed plant poachers to. TPP will return to this topic shortly as he just acquired a rare locally endemic Magnolia.

Beware the glow

Plants attract animals for various purposes, mostly dispersal of pollen and seeds, but no uses more nefarious than to supplement their nutrients.  So called carnivorous plants don't eat animals for food, but they grow in nutrient poor habitats and capture prey to provide mineral nutrients.  Floral biologists have know for years that flowers absorb and reflect ultraviolet light providing very distinctive patterns for insects whose vision extends into the UV wavelengths.  But this is quite a surprise; pitcher plants also reflect UV light, or glow in UV light, to attract insects to their deaths.  The image here, borrowed from the authors of this study reported at the National Geographic web site, shows a tropical pitcher plant (Nepenthes), in both white and UV light, and the lip of the pit fall trap glows brightly when illuminated with UV light.  How many times has TPP looked at these things and never had it occur to him that they might use UV to enhance their effectiveness?  Dang, but this happens all the time in science, in biology.  So kudos to the authors for seeing more than the rest of us. 

Green Swamp - Carnivorous Plants Abound

The intertubes have made this a much smaller world, and a long-time reader figured out that we were vacationing only about 10 miles apart.  As a nice botanical gesture, she recommended that the Phactor visit Green Swamp.  Somehow we did manage to get a couple of hours away from the family mob and have a look-see.  None of the urban sophisticates comprising the rest of our family demonstrated even the least interest in tagging along to a swamp.  Well, it was their loss.  Even without knowing the area or having any guidance the Phactors managed to see sundews by the dozens (2 species it seemed, but haven't checked yet), showing off their glistening and deadly glandular hairs, bladderwort in flower, venus flytraps, and pitcher plants, all of which are "carnivorous" plants, trapping insects or other inverts for purposes of augmenting their nutrient supply.  Nitrogen is generally hard to obtain in these wet acidic environments.  The pitcher plants were past their prime, so see this blog post from our friendly tipster to see them a bit earlier in the season.  Image-wise you'll have to make do with a sundew.  There were also two milkworts, two Rhexias, a yellow-eyed grass (Xyris sp. ?), and lots more in flower. The Carolina coastal region is quite famous for such plants, some of which are endangered because of habitat destruction and human predation.  

Biology of carnivorous plants

People have a certain funny fondness for carnivorous plants: pitcher plants, venus fly traps, sundews (maybe my favorite), Audrey II, bladderworts, and so on.  They are among the favorites of visitors to our glasshouse.  These are all green plants, and therefore photosynthetic autotrophs, but they live in nutrient poor environments, so the prey they capture, mostly insects, provide those nutrients.  HT to AoB blog for pointing out this review of the biology of carnivorous plants.  And so we feed your curiosity.

Carnivorous plant terrarium

A reader asks: "Hi, I'm trying to set up two terrariums. They both will consist of carnivorous plants. I am considering Venus fly traps, Sundews, Butterworts, and Sarracenia purpurea. What combinations would be best for optimal growth and beauty. Also where would be a good place to buy them from. Thank you."

None of these plants are truly carnivorous in spite of what they are called. All are photosynthetic autotrophs, but all are natives to habitats, mostly acidic wet lands, where nitrogen is a limiting necessity. Carnivorous plants capture insects and other invertebrates and use them as a source of nitrogen. As wetland plants they require pretty high light and humidity, and of course, our homes are basically dimly lit deserts, a bad combination for most plants. A terrarium can solve the humidity problem. These plants also do best in low pH (acidic) conditions so that means using a growth medium high in peat moss, in fact growing sphagnum moss, sort of pre-peat, is an excellent idea. So basically you're trying to create a bog although they do not like standing in water. Sundews (pictured) do seem to like saturated soils. Tap water in most places tends to be somewhat limey, basic, so capturing rain water for your terrarium would also be a good idea. None of the plants you mention are large, but for starters it would be best to pot them individually and surround them with sphagnum, which may decide to grow if some viable asexual propagules remain. The pitcher plant can get 9-10" across, so it's the biggest. Small plants like sundew look best in clusters or clumps. Providing bright indirect light may be the most difficult problem best dealt with by putting a plant grow light maybe 18" above the terrarium.

Purchase of carnivorous plants is pretty easy. Lots of online sources are available and the Phactor tries to avoid endorsements (they refuse to pay up). Some pretty well-known sites provided without endorsement are the Carnivorous Plant Nursery, Bug Biting Plants, and Predatory Plants. They are not even uncommon in garden shops and even some big box stores. Care and feeding information is also fairly common. These are not actually difficult, but neither are they easy plants to grow successfully. One problem is the North American species are temperate, and a cold season of dormancy seems necessary to keep them happy. But feeding them flies and such can be quite a bit of fun.

Real Crappy Plant Research

If a plant is green, why be carnivorous? And if a plant if carnivorous, why be green? This was a central question surrounding the phenomenon of carnivorous plants. And science has known the answer for a long time.
Plants are awash in nitrogen (70% of the atmosphere), but plants can’t use gaseous nitrogen, and lack of this critical nutrient often limits plant growth. Some plants use bacterial symbionts to help them acquire nitrogen, e.g., legumes-Rhizobacter; mosquito fern-Anabaena. But carnivorous plants use their various trap devices to capture animals and acquire nitrogen from the digestion or decomposition of their bodies.

Since its discovery people have thought that the giant pitcher plant of SE Asia caught really large animals, things like mice, which for a plant is pretty large prey. Nice idea, but the "body" of evidence was always lacking. It turns out that this pitcher works in a different way. By positioning a nectar reward on its lid, small mammals like tree shrews are positioned such that when they defecate, the “results” end up in the pitcher. And when you think about it, this particular pitcher does sort of look like a toilet.
So this is one more way plants interact mutualistically with animals to acquire needed resources, but you can decide what to call this since it isn’t really an animal-eating plant anymore.

HT to Zooillogix.