It is a well-known fact among our wild orchids, such as Cypripediums and the like, that they do not seem to spread, though apparently seeding freely. If there are a thousand plants in one spot to-day, likely there will be but a thousand in the next twenty years. The same fact has been noted in the Old World, and a correspondent of the Gardening World tries to account for it:

"A single capsule of some of our commoner native species would produce over 6,000 seeds, while some of the exotic Maxillarias have been calculated to contain about a million. This number is probably much exceeded by Cattleya gigas, and seeing that the progeny of the third generation of a species producing the lowest mentioned number of seeds is sufficient to cover the entire surface of the globe with plants, it is very obvious that a very small percentage ever become plants at all. Their minuteness and the very little nutriment they contain precludes the idea that they offer great temptations to, and are destroyed by birds. Again we see that our native orchids thrive admirably when they have succeeded in establishing themselves, a fact which suggests the idea that they either do not germinate or are killed in the process of germination or soon after. The length of time they require to complete this process must be fatal to their well-being in this our changeable climate, where the necessary conditions as to heat and moisture are too inconstant and variable to allow the seedlings to establish themselves; whereas, the seedlings of other plants are ready to spring into life and activity upon the accession of the proper degree of heat and moisture, those of orchids are unable to do so".