I have learned a great bit from reading the sections of Darwin's Insectivorous plants available in e-book format here: e-book
or here: Original book in PDF with Illustrations
ICPS on growing from seed: Germination Guide
Pictures: Rotundifolia Humbolt Co. is Big Lagoon!
IMHO you should read the e-book then look at the pictures in the original book if you're interested.
Lets get started! Rotundifolia are coming out of dormancy in San Diego! The plants I have available are from Big Lagoon and Butterfly Valley CA. I am interested in using these plants because they are native to the CA coast, so I'll be able to know how to cultivate a plant native to my state. They weren't easy to get!
Drosera Rotundifolia, or the common sundew, is found nearly everywhere except Antarctica. It is small, ranging from 13cm to 3 cm with 6cm being about typical to the U.S. In nature, it grows in beds of sphagnum moss. I will be test-growing some in peat and sand. In fact, I germinated 1 seedling with the media...but fungus gnats got to the pot so that may be why most haven't grown. If you want to sow rotundifolia seed, I recommend that you stratify it in the fridge with some moist LFSM for four-six weeks. Then, spread the LFSM on a pot full of moist peat and place it in a bag. Put this under lights and they should start growing. Even better, sow on your bog or on a pot outside in the fall. There will be plants for you in the spring.
The tentacles and leaf close around prey slowly, even slower than d. capensis. I placed a fly on a leaf of one emerging from dormancy, and it took a full day for infliction to occur...probably due in part to the fly being just recently killed, the cold temperatures, and the state of the plant. The tentacles are solidly built, with long ones extending from the base of the leaf. According to Darwin, they become inflicted if something (anything) touches the surface of one of the glands [on the tentacle] even if it is 1/1000th of an ounce. Please note that only a single tentacle would be inflicted with a substance this fine. He was puzzled why dust and debris left tentacles unaffected. Of course, matter with nitrogen or nitrogenous matter caused much more movement. That is why flies and blood worms excite drosera so. Darwin observed infliction in under 10 minutes with highly excited young leaves.
Drosera routdifolia is a small plant. The biggest seen have been under 6 inches in diameter. Most of that is petiole. Even though they are typically about as big as a half-dollar, the dew is really sticky! Maybe it is the design of the leaf. Compared to d. capensis, I think d. rotundifolia dew is more powerful. One thing interesting to note is that d. rotundifolia always brings its prey into the center of the leaf while feeding. The exterior tentacles always inflict inward--in fact, all the tentacles inflict inward toward the center. the prey is brought toward the center by this movement. Once the prey is in the center of the leaf, the leaf forms a cup to hold the juices.
Here are the plants I will be using. They are just waking up:
From Big Lagoon:
From Butterfly Valley:
with the fly I discussed earlier:
This thread is brought to you by Not a Number, who asked me to read up on rotundifolia and share my findings. He also donated seed from a small California population for the research. It is also brought to you by Flytraplady(5?) who sent me the plants that are coming out dormancy now (in a trade).
To Be Continued as I experiment!