a, luxurians (J. Ag.). 
Callithamnion luxurians J. AGARDH Sp. Il p. 14. 
Chantransia luxurians Kyuın l.c. p.117 fig. 26. 
Callithamnion virgatulum Crouan Alg. mar. Finist. p. 116. 
Chantransia virgatula THURET in Le Jol. Liste p.106; Kyrın (1907) p. 116 fig. 25; BoRGESEN, M. A. Fær. 
p- 351 fig. 52. 
110 
Trentepohlia virgatula FarLow Mar. Alg. New Engl. p.109 pl. X fig. 3. 
Fig. 37. 
Chantransia virgatula a, luxurians. A, 
plant with sporangia. B, basal part. 
part of young plant. 
260 :1. 
Cc, 
part of 
basal 
This form which corresponds to the Ch, 
virgatula in the common restriction of the au- 
thors is the commonest form in the Danish 
waters. It has two or three generations of 
long filaments, which are straight, up to 2mm. 
long, 10 to 14 » thick, more rarely up to 16 y 
thick or even thicker, consisting of cells 3 to 
5 times as long as broad. There is a distinct 
contrast between the long filaments and the 
branchlets which occur in great number, one 
or two on each cell of the filaments, in the 
first case often secund, in the latter usually 
opposite; they are usually 1 to 3 cells high, 
unbranched or branched and bear generally 
two or more sporangia and most frequently 
also one or more vigorous hairs. The spor- 
angia are monosporous, ovate or broadly ellip- 
soidal 17—21 (—26) » long, 13—16 (—19) » broad. 
Under this species I have included two 
- forms regarded by Kyrın as distinct species, 
namely Ch. virgatula and Ch. luxurians, because 
I have not been able to distinguish them after 
the alleged characters. In most of the Danish 
specimens the thickness of the filaments varies 
between 11 and 13 y, thus within the limits 
indicated for Ch. luxurians by Kyrın, and the 
dimensions of the sporangia also agree with the 
measurements indicated for this species. On 
the other hand, the specimens with thicker 
filaments, thus agreeing better with Ch. virga- 
tula KyLın, had not shorter, approximately glo- 
bular sporangia as indicated by Kyrın, but 
were of the same dimensions. The thickest 
filaments were found in some specimens from 
Lysegrund in Ks (9,5 meters); they varied from 
13 to 20 % in thickness, the cells were thick- 
