You are amazingly perceptive! Lucky bamboo is a type of dracaena (Dracaena sanderiana), not a true bamboo. Your dracaena cuttings are growing into their true form. These dracaena poles, with their segmented stems, make a tropical-looking grove, but the display is temporary. Dracaena roots in water and may live in it for several years if periodically fertilized. If you want to retain the appearance of stems with few leaves, you can trim back the foliage on your plants. Or you could take your rooted cuttings out of their current container and pot them up to grow as a regular houseplant. The variegated form of lucky bamboo (green leaves with white edges) is a common houseplant known as ribbon plant.