310 



Dansk Botanisk Arkiv, Bd. 3, Nr. 1. 



Danish islands; comp. J. Agardh, Spec. Alg., vol. II, p. III, p. 1230. 

 Later on Ørsted collected it at St. Thomas and St. Croix. 



St. Croix: Near Green Cay Estate and at the entrance to the lagoon 

 of Christiansted (both places washed ashore). St. Jan: Dredged in many 

 places in the sound between this island and St. Thomas. 



Geogr. D i strib.: West Indies. 



Wrightiella Schmitz. 



1. Wrightiella Tiimanowiozii (Gatty) Schmitz. 



Schmitz, Fr., Die Gattung Lophothaha J. Ag. (Ber. der deutsch, bot. 

 Ges., Bd. XI, 1893, p. 222. Falkenberg, P., Rhodomelaceen, p. 559. 



Dasya Tumanowiczii Gatty in Harvey, Nereis Bor.-Am., part II, p. 

 64. KüTziiVG, Tabul. Phycol., vol. XIV, tab. 63. 



The plant has four pericentral cells which on a later stage are 

 more or less covered by a cortical layer (Fig. 314). 



What especially distinguishes this plant are the 

 polysiphonous, short, spinelike endogenous branchlets 

 found scattered upon the thallus. Moreover it is 

 endowed with exogenous, mostly short hving, mono- 

 siphonous side-organs. These Falkenberg refers to 

 as "monosiphone Kurztriebe (nicht Blätter)", I call 

 them trichoblasts. 



The plant increases by means of an apical cell 

 from which flat segments are cut off (Fig. 313); from 

 these the trichoblasts begin to grow out long before 



WnfhuTaTu- ^^^ Segments are divided. 



manowiczii The trichoblasts are placed in a screw line, with 



SdimS. ^ divergency of 14 of the periphery, upon the main 



Summit of the hlament (Fig. 314) and consist of a monosiphonous 



(About' 500:1) "^^^^ ^*^"^' ^^^"^ which the monosiphonous branches 



issue spirally with a divergency of V« — Vj- In 



the sterile plant the cells in the trichoblasts are small at the 



base, increasing evenly until somewhat above the middle of 



the whole trichoblast, then tapering slowly to the blunt or 



generally acute ends of the filaments (Fig. 315). The cells of 



the trichoblast are cylindrical or barrelshaped with thin walls. 



In the trichoblast both the tetrasporangia and the cystocarps 

 are developed. When we have to do with the last mentioned organs, 

 which I have not found in my specimens, the trichoblasts, according 

 to Falkenberg, are more persistent and the lowest segments be- 



