Note from Mary Sue: I'm passing on this reply from Doug minus the image that cannot be included in posts to this list. kuang huang, You have to watch carefully to acquire sime if the more difficult ones. You mentioned Paramongaia weberaueri. Not only is it difficult to find someone who has offsets, but when you do, (depending on the age/size of the bulb), the price will be rather high. To buy a mature bulb (blooming size) the person MAY be asking up to $100 or more. Not many people have it. I had a bloom last year. I thought that I may have some seeds, but it "decided" not to develop. I was fortunate enough to acquire Hippeastrum intiflorum a few years ago and it set seeds. As they developed, I discovered that I was the only one in the world to have extras available for trade or sale. The country of Argentina put a "halt" on bulbs being taken from their country, so I even had a person from Argentina asking for one. Being fortunate enough to have these for "trade", I was able to acquire some of the "rare" Hippeastrums in trade. You just have to be patient and purchase one or two rare ones and try to "multiply" them (unless you have sufficient funds to purchase the "rare" ones). Best of luck, and don't give up. Doug Westfall