Tin: coDiuMs of the juan fkrnandkz islands 59^5 



Thalliis forma magnitudineque maxime variabilis, typice clongatus, cylin- 

 tliiciis, basi rcpctite, supernc remote et sparse inaequaliter dichotomus, usque 

 ad lOO cm. ( + "') longus, 0.5 — 1 cm. uscjue ad (in partibus dilatatis complana- 

 tisque) 3 cm. latus; utriculis megaphysis, 800 — i 250 ;j. longis, 50-500 ;j, latis, 

 typice anguste usque ad latissime clavatis, apice late rotundatis, rotundato- 

 tiuncatis, aut fornicato-truncatis, membrana apicali plus minusve incrassata 

 usciue ad 15.- (-30) m. crassa et stratosa, pilis aut nullis aut in verticillis irre- 

 gularibus sub apice positis; gametangiis elliptico- usque ad lanceo-ovoideis, 315 ;j, 

 longis, 75 ;j. { — 90 ;j.) latis, in verticillis irregularibus, 450 — 500 a sub apicibus 

 positis. 



Forma t\-picum: — utriculis piliferis. 



Type in Herb. Kew, No. 65. 



Masatierra: No. i, beach drift, Bahia del Padre, Jan. 26, 1917; No. 4, 

 lower littoral, station 2 B, Jan. 26, 191 7; No. 11, from 10—25 meters, on 

 bottom of sand and stones, opposite Pangal. 



Masafucra: No. 6, brought up in lobster trap, Bahia I'olten, Feb. iG, 

 1917; No. 7, Loberia, Feb. 16, 1917; No. 8, beach drift, Loberia, Feb. iG, 1917. 



Forma psilopJiysalicuni: — pilis utriculorum egentibus (psilophysis). 

 Type: Herb. Univ. Calif. No. 549099. 



Masatierra: — No. 3, beach drift, Bahia del Padre, Jan. 26, 1917; No, 

 10, from 30—40 meters, on sand, shells, and stones, Cumberland Bay, Mar. 



It may be questioned whether the Juan Fernandez plants should all be 

 placed under the same species and it may also be questioned, in case it may 

 be decided that they are all only variants of one species, whether to segregate 

 them from Codiian decoyticatinn (W'oodw.) M. A. Howe. These two questions, 

 and their various implications, come immediately to the front, not only in 

 the study of the material collected by Dr. SKOTTST3ERG, but also in any 

 attempt to arrange any group within the Dccorticata Anepsiotes (or cousin- 

 ship). From one point of view, it may be more simple to recognize only 

 one wide-spread but geographically very discontinuous megaspecies, but, on the 

 other hand, this very discontinuity suggests possible necessity of segregation. 

 The Decorticata is a well marked group, to be separated from the Tovientosa 

 and the Elongata groups without unusual difficulty. Studies of the types of 

 Ulva decorticata Woodward and of Codiuui clongattivi C. Ag., in connection 

 with earnest attempts to determine the characters of C. dkhotomitm (Huds.) 

 Setchell {C. tovuntosiim (Huds.) C. Ag.), show both general habit as well as 

 utricular differences such as have been indicated elsewhere (see Setchell, 

 Univ. Calif. Pub. Bot., 17: 187 — 190, pi. 26, 29, 1933). The result of these studies 

 indicates that the membership of Decorticata possess a large (megaphyse) 

 utricle as contrasted with the comparatively small (microphyse) utricle of C. 

 dichotoinuin or the intermediate (anamesophyse) utricle of C. elongatum. The 

 infra axillary dilations, so common in C. elongatum (type), are not found in 

 C. dicliotomuni but do occur, though usually sporadically, also, in some forms 

 of C. dccorticatiun proper. They are present, for example, in specimens col- 



