|Byron ||06-03-2009 11:10 AM |
All Echinodorus flower by sending out a runner that will wind its way toward the surface. Along the runner, nodes develop from which flowers and daughter plants emerge. I have maintained swords for years in various aquaria, and while they all (pretty much) send out the runners and produce (often) numerous daughter plants, none have ever flowered in my aquaria. The flower buds are there (I currently have several on a flower spike that recently appeared on my Echinodorus macrophylum) but don't open. I note that Peter Hiscock comments in his book "Encyclopedia of Aquarium Plants" that "not all aquatic plants are likely to produce flowers in the aquarium." I suspect the reason for this is two-fold. One issue may be the lack of brighter light and nutrients, water level and air space above the water. As you (SC) know, I have moderate-low light and no CO2. I believe mega light and CO2 (and increased substrate nutrients to balance) might result in flowers. However, I think there is a second reason that may be related.
I have seen them flowering in the store tank. I suspect this is the result of how they are cultivated by nurseries, which is as bog plants emersed; that is why they will grow different shaped leaves when planted in an aquarium from what they had when purchased in the store (unless they have been in the store tank for some time). It seems probable that some of the species need to be grown emersed rather than submersed in order to flower, much as the Cryptocoryne of SE Asia. Most Echinodorus in SA are bog plants that are submersed half the year, and flower during the emersed half. Some species are true aquatic plants; Heiko Bleher and others have observed these in the Rio Negro and I believe Rio Guapore systems. But according to the authorities, many Echinodorus are true bog plants that adapt well to permanently submersed conditions, but may not flower for that reason.
As I'm happy with the look of my aquaria without the additional expense of CO2 and more light (which would be too much for my fish and need other measures to deal with that) I am quite happy when I see the runners and flower spikes with copius daughter plants even though they don't flower. I have frequently observed the same thing in the Amazonian displays at the Vancouver Public Aquarium and Marine Science Centre; runners up to the surface in 5-6 feet deep displays and daughter plants all along. I have had Annubias nana flower, several times, underwater; and Aponogeton flowered above water when I had it in a tank that had considerable daylight from directly overhead in a solarium.