Echinodorus produce flower spikes (sometimes just one, sometimes two or even more at a time) which generally (when the plant is grown permanently submersed) develop daughter plants and not flowers. Like those you have. Some plants seem not to do this, others will. To my knowledge all runners are above substrate, even in the pygmy chain swords (E. quadricostatus, E. tenellus) the runners usually remain just above the substrate so the daughter plants can easily root, though I have some that are higher in the water column probably due to light conditions.
You can trim off large swords by removing the outer leaves. Always remove the outer leaves; the new growth occurs from the centre of the crown. Removing outer leaves on some of the larger Echinodorus can force the plant to develop smaller leaves, and also more of them. Like all Echinodorus (to the best of my knowledge), E. osiris produces adventitious plantlets as mentioned.
Peter Hiscock does mention that if large enough the plant can be divided by cutting through the crown with a sharp knife. To be safe, not knowing how large your plants are, I would suggest trimming off the outer leaves and see if this works. You can also of course move the plant, Echinodorus don't mind being transplanted, if not done too often.