344 8 



The question now arises if we also find in these very varied localities 

 different types with regard to the development of the rhizome and roots and with 

 regard to the mode of growth on the whole. Svedelius for Ceylon has distinguished 

 between 3 types, namely, the Caiilerpa verticillata type, sand Caulerpas and rock 

 and coral Caulerpas. This is in good accordance with the divisions I have given 

 in my earlier paper. We have namely in the Danish West Indies the following 

 groups: sand and mud Caulerpas, rock and coral-reef Caulerpas and finally the 

 Caulerpa verticillata group which I prefer to call the epiphytic or mud-collecting 

 Caulerpas. 



(l)The epiphytic or mud-collecting Caulerpas. To this group belongs 

 Caulerpa verticillata, which in the Danish West Indies is very common on the 

 mangrove roots, as I already have pointed out in my paper (5, p. 55 — 56). As a thick 

 dark-green sheath it covers the roots of the mangroves and if we try to draw it 

 loose from these we commonly get a whole clump, which on the under side shows 

 itself to consist of a dense tissue of the nearly thread-fine rhizomes which are 

 woven together and between which quantities of fine mud and different organic 

 particles are mixed together. If we try to separate the plant more without spending 

 greater care on it, we commonly only obtain some tuft-like pieces without rhizomes 

 such as we often find in herbaria, and is in accordance with Reinke's figure (27, 

 pag. 7). Reinke indeed had the opinion that the plant probably had no rhizome. 

 As I have mentioned (5, p. 56), and later on I shall come back to it in more detail, 

 this is not right. By a careful preparation of one of the above-named dense tufts, 

 one can commonly get somewhat easily such a plant as shown in figure 1. 



As mentioned we find mud and organic objects packed in between the thread- 

 like rhizomes and that often in considerable quantities. Even if we collect the 

 plants in clear water and these apparently are quite clean and only touch the 

 mangrove roots, the water directly becomes niuddy from tlie mud present and we 

 have commonly some work in clearing the plant before preparation. 



In Ceylon Svedelius did not find Caulerpa verticillata epiphytic but on the 

 contrary growing on low rocks covered with mud and sand in the mouth of a 

 stream. It was here growing in dense tufts collecting sand and mud between the 

 rhizomes and that often to so great an extent, that there could be danger of over- 

 sanding; but as pointed out by Svedelius, the plant is by means of the oblique, 

 even often vertically placed rhizomes soon able to grow out of the sand again; by 

 reason of this capacity Svedelius says that it "reminds us to some extent of many 

 dune grasses". Only once have I found C. verticillata growing in a locality, I think, 

 similar to those at Ceylon. In the harbour of St. Thomas on the northwest end 

 of the Hurricane Island, in the narrow and shallow sound which lies between this 

 Island and St. Thomas, I have found C. verticillata growing partly on an old bridge 

 built of limestone and piles, partly also spreading itself from here somewhat on 

 the stones etc. lying on the bottom itself. Likewise as on the mangrove roots it 

 was filled with mud and organic material, but any danger of being oversanded is 



