1899] Ganong, xs Polyembryony in Opuntia vulgaris 127 
Phyllitis zosteraefolia Reinke. Magnolia, Mass., Miss C. E. Clarke ; 
also at Newfoundland. 
Phyllophora rubens (Good. & Wood.) Grey. Newport, R. I., Mrs. 
W. C. Simmons. Only a single specimen, and that doubtful; not 
otherwise known in America; should be carefully looked for. 
Polysiphonia vestita J. Ag. Martha’s Vineyard, Miss Laura Jerne- 
gan. Only a few plants. 
Porphyra coccinea, J. Ag. Hampton Beach, N. H., F. S. Collins. A 
single frond of Desmarestia aculeata, washed ashore, covered with the 
Porphyra; not otherwise known in America. 
Scaphospora Kingti Farlow. Edgartown, J. D. King. 
Sorocarpus uvaeformis Prings. Martha’s Vineyard, Miss Colt. 
Ulothrix collabens (Ag.) Thuret. Nahant and Swampscott, F. S. 
Collins. 
The writer would be very glad to receive specimens of any of these 
species from localities other than those named, or, in the case of the 
rarer ones, from the same localities; and, in general, any species new 
to our limits, or from points beyond the previous range. As far as 
practicable, he will be pleased to assist correspondents in determining 
doubtful forms, with the usual understanding that a specimen of each 
may be retained, if desired. , 
POLYEMBRYONY IN OPUNTIA VULGARIS. — A. phenomenon of much 
scientific interest, though of no great frequency, is polyembryony or 
the production of more than one embryo from a single seed. It 
occurs in Opuntia vulgaris, as described and figured in the Botanical 
Gazette for April, 1898. The material used in that study was, how- 
ever, from plants long grown in a botanic garden, and the polyem- 
bryony has not yet been observed in plants growing in a wild state. It 
is possible, though unlikely, that wild plants are not polyembryonic, 
and it is desirable that observations upon the point be made in the 
field. As the species occurs in New England, some of our botanists 
may have opportunity to study it this summer. If polyembryonic speci- 
mens are found, they should be preserved, preferably in a two per cent 
solution of formaline. The polyembryony shows itself in two ways : — 
first, in the production of two or more perfect embryos, one usually 
much larger than the others, from a single seed; and second, in single 
embryos composed of two or more variously united, thus showing 
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