116 DR. Е, BÜRGESEN ON FUCUS SPIRALIS, LINNÉ. 
1851) *. In this work Thuret describes (p. 57) the new species Fucus platy 
carpus, Which was distinguished firstly by its hermaphrodite condition in 
contradistinetion to Fucus serratus, ceranoides, and vesiculosus, which have 
unisexual receptacles +, and secondly, and especially, by its *receptaculis 
lateralibus,” which were so different from the hitherto known form of Fucus 
spiralis, that it is quite natural that Thuret should consider it to be a new and 
characteristic species. 
However, if Thuret had not happened to work on the coasts of Normandy 
but instead on the coasts of the Færües or Norway, he would certainly 
have arrived at another conclusion. He would then have discovered that 
the hermaphrodite condition is not only characteristic of Fucus spiralis but 
also of Fucus inflatus 5 he would furthermore have been able to study the old 
well-known forms of Fucus spiralis, and would of course have used Linné’s 
name. 
The strange form of the var. platycarpa in conjunction with the discovery 
of its hermaphrodism, which Thuret thought characteristie of it alone, made 
him introduce his species. 
Not until much later on (1878) did Thuret and Bornet give in * Etudes 
Phycologiques’ an account of forms, described by earlier authors, which, 
in their opinion, ought to be classed with the Fucus platycarpus, and they 
mention here, first of all Fucus spiralis, L. et auct. partim. 
It is interesting to see that the brothers Crouan, the year after, in their 
excellent exsiccata, © Algues marines du Finistère,” No. 103, distributed a 
Fucus which they indicate as К. vesiculosus var. spiralis= Fucus spiralis, L., 
a specimen closely allied to the var. typica, whereas the next number 104 is 
var. platycarpa, by Crouan called Fucus vesiculosus var. evesiculosus, Cr.= 
Fucus evesiculosus, Bory = Fucus Thuretii, Le Jolis MS. Thus the brothers 
Crouan consider here the two forms as different, and in contradiction to 
Greville and Harvey as varieties of Fucus vesiculosus. It is also rather 
peculiar that they do not use Thuret?s name for No. 104, but this may 
possibly be due to the short time that elapsed between the publication of 
Thuret?s work and Crouan’s exsiccata. If we now follow Fucus spiralis, L., 
and Fucus platycarpus, Thur., up to the present time we shall discover that, 
as a rule, they are considered as different species, 
Areschoug has thus in his paper: **Slügtena Fucus (L.) Decaisne et 
Thuret och Pycnophycus Kütz., jemte tillhörande arter ” (Bot. Notiser, 1868, 
р. 106), Fucus platycarpus, Thur., and Fucus Sherardi, Stackh., a. spiralis. 
* In an earlier paper, which Thuret had already edited together with Decaisne, 
* Recherches sur les anthéridies et les spores de quelques Fucus ” (Ann. Sc. nat., sér. 3, 
vol. iii. 1845), it is shown that dicecious, as well as hermaphrodite, species of Fucus are to be 
found, 
T Regarding Fucus ceranoides this statement of Thuret is not quite right, as Fucus 
ceranoides, аз Le Jolis (Liste des Algues marines de Cherbourg, 1563, p. 95) has pointed out, 
may sometimes appear dicecious, sometimes hermaphrodite. 
