The two closely allied genera of ferns, Elaphoglossum and Rhipidopteris, one very large and the other very small, were included in the composite genus Acrostichum L. by early botanists. It is now generally agreed that they are not nearly related to the type species of Acrostichum, namely A. aureum L. The first botanist to suggest that they be separated was H. Schott. In his Genera Filicum, he proposed a segregate genus from Acrostichum which he called Bolbitis.l Following the description of this genus there is the following note: "Praeter Bolbitin alia duo genera: Elaphoglossum et Rhipidopteris, ab Acrostichis genuinis sunt segreganda. Prioris generis exempla sunt: E. simplex, conforme, apodum, viscosum, vestitum, etc. (Acrost. simplex, conforme etc. Auctorum); posterioris: Rh. Humboldtiana, peltata, foeniculacea et tripartita (Acrost. flabellatum, peltatum, etc., Auctorum.)" Christensen, in his Index Filicum, adopted these genera as validly published by Schott, but they cannot be so considered under the International Code of Botanical Nomenclature. There is not a word of description. Article 42 specifies that the name of a genus is not validly published unless it is accompanied either by a description of the genus or by the citation of a previously and