244 
F. W. Oliver. 
Dipteris quin quefareata, and then in Dipteris conjugatn a webbing of 
them to form a broad expanse. Parallel with this goes evidence of 
fission of the sori leading to great increase in their number, together 
with the reduction in the number of sporangia in each sorus. And 
finally there is the further progression from a sorus of the type of 
the “Simplices,” with all the sporangia simultaneous, to a condition 
indicative of the “ Mixta:,” where the sporangia of a sorus are of 
different ages. It must be noted also that such a transition within 
the genus from a simultaneous to a successive type of sorus is 
paralleled in the case of the genus Dennstaedtia, where, however, 
the step is from a sorus of the type “ Gradatze ” to that of 
Mixta; 1 
Since the changes in all these characters run parallel, it seems 
highly probable that they indicate a progression from a type com¬ 
parable with that of Matonia to the broadly expanded type of 
Dipteris conjugatn. 
1 Bower, F. O. (’99). “Studies in the Morphology’ of Spore- 
producing Members. Part IV. The Leptosporangiate Ferns.” 
Phil. Trans. B. Vol. 192, PJ. 7, Fig. 132. 
THE BOUCHE D’ERQUY IN 1907. 
[Figs. 15, 16.] 
rnHE studies on the halophytic vegetation of the Brittany salt- 
marsh—commenced in 1904—have been continued during 
the present year. Since the writing of the last report' three minor 
visits have been paid in addition to the annual expedition (lasting 
from the 1st to the 14th of September) in which twenty persons 
took part. 
Chromatic Instability : Transplantations. 
It may be recalled that the more stable portion of the 
vegetation-covering on the Erquy marsh falls into a limited number 
of distinct types or associations, viz: —the Juncus-zone on the 
periphery; the Suaeda-plateaus, slopes and hillocks, where the 
1 New Phytologist, Vol. V'., p. 189, 
