1 



MacMillan : Observations on Nereocvstis 279 



or. four such sori may occur, their ends separated by but a few 

 centimeters of sterile tissue. The leaveis which bear the sori are 

 rather broader than the sterile leaves. Fruiting patches arc very 

 conspicuous on account of their slightly lighter color than the 

 sterile tissues. Oliver writing in 1887 states categorically that 

 nothing is known of the reproduction of Ncreocystis, but Arcschoug 

 in 1876 observed the sporangia and paraphyses together with some 

 young forms, as indicated in his paper in Bot. Notiser, and after- 

 wards in 1884 returned to the subject in his Obscrvatioiics Phyco- 

 locr'tcac where a brief systematic description is given. :\Iy own 

 researches have cleared up the origin of the sporangia and para- 

 physes apd I have been able to follow the development of the 



sorus from its first inception. 



Ecology. The habit of mature Ncreocystis plants is to attacli 



themselves in channels where the tides are swift and beds of the 

 plant are to be looked for in tidc-wa>-s. I think that plants which 

 are adapted to life in strong tide-ways and tide-rips should be dis- 

 tinguished as a special ecological sub-class of hydrophytes distinct 

 from such plants as Fontinalis which grow in river- channels and 

 may be termed rhcophytcs. Previously I have noted the adapta- 

 tion of certain limnetic plants to withstand the impact of surf and 

 proposed for them the name of cnmapliytcs. I now venture to 

 sun-rrest that plants \\V^' Ncreocystis or Alaria be regarded as t>-p- 

 ical of the tide- way habitat and be known as palirJicopJiytcs. \\ hen 

 the tide'is not running the pneumatocysts float more nearly per- 

 pendicular and show as round bulbs at the surface of the sea, but 

 when the tide begins to run tension is exerted on the stipe and 

 holdfast and the long retort-shaped pneumatocysts lie lengthwise 

 with the current. The leaves are always somewhat submerged ; 

 especially is this true when the tide is running — a habit which 

 protects their more delicate bodies from the destructive friction and 

 impact of the surface. When the tide changes the shifting of the 

 great pneumatocysts is sufficient in force to overturn small skiffs 

 which ma}' be caught among them. But larger boats find a 

 Ncreocystis bed a safe anchorage if a storm overtakes them while 

 near the rocks of a leeshore, and Paget Sound fishermen often 

 anchor their boats to a dozen of the Ncreocystis pneumatocysts and 

 have no fear of being blown upon the rocks, so firmly are the 



