152 



whole the same appearance as the small compact part shows. On 

 specially exposed localities the assimilators grow smaller and smal- 

 ler, at the same time being less numerous; in such localities the 

 plant nearly entirely consists of the rhizomes. 



In the most exposed localities the plant becomes so reduced 

 and different in appearance that I have described it as a special 

 form: f. rediicta (Fig. 122). This form is characterized by its, in 

 all respects dwarf-like organs. The rhizomes are scarcely a milli- 

 meter thick and bear on the downward side numerous richly rami- 

 fied rhizoids, by means of which it is firmly fastened to the sub- 

 stratum. On the upward side the rhizomes are either naked or 

 have short, often only a centimeter high assimilators with more 

 or less irregularly shaped, often nearly cylindrical ramuli; only 

 more seldom do we find more normally developed ramuli swollen 

 at the apex. The ramuli often grow out to new rhizomes (see 

 Fig. 112 rf and e) and contribute thus to producing the entangled 

 tissue of the rhizomes. This form was found in large mats covering 

 the most exposed places where Caulerpa is to be found at all. The 

 sea breaks fiercely over the alga, which motionless bids defiance 

 to the waves and just in its firmness possesses the necessary pro- 

 tection. Following the plant from these the most exposed places 

 to more sheltered we have the most even transitions to the typical 

 form of var. clavijera. Of all Caulerpas occurring in the Danish 

 West Indies, this form is certainly the one which can grow in the 

 most exposed places. 



Yet a third form of Caulerpa racemosa is found on rocks and 

 coral-reefs, namely, the form to which I have given the name var. 

 occidentalis (Fig. 123).) This variety which I earlier in agreement 

 with Reinke referred to var. Chemnitzia and under which name 

 I have distributed it in the Exsiccatge of Wittrock & Nordstedt, 

 I now believe on more thorough examination to be separated from 

 the C hemnitzia-gr oup and thus to be considered as a special variety. 

 I have used the name of J. Agardh for it, as I think there is no 

 doubt that my form is identical with the form of Agardh, as Svede- 

 Lius (1. c, p. 130) has also maintained. J. Agardh gives the fol- 

 lowing short diagnosis (1. c. p. 37): »frondibus erectiusculis fere 

 claveeformibus, inferne laxe ramentaceis supcrne dense imbricatis«. 

 And in the description further down on the page he adds: »In forma 

 occidentali s?ppius ramenta ad rachidis partes supremas donsiora, 

 immo dense imbricata hunt, parte apotheciiformi extrorsum oblique 

 versa, rachides ita omnino obtegentia; frondes his locis immo digi- 

 tum minorem crassa3«. From var. Chemnitzia this form differs by 



