The reason you can't find those specific seeds is that bamboo only produce seeds at great intervals...like every 20-150 years. And when a bamboo species starts to flower, it often does so worldwide over a several year period, and then dies. The only seeds you can get are the few available ones that are flowering right now. Those of us who grow bamboo typically get our bamboo as divisions of live plants, and occasionally grow from seed. However, you should also know that seed frequently does not grow true to form, so you may get a very different bamboo if you try that. Finally, if you do find some seeds you want to grow, you need to insure that they are fresh, as bamboo seed loses viability quickly. Also, be aware that a bamboo grown from seed will often take 5 years to get to head height.