97 



grows in thickness with the thickness of the frond. In the node I observed from 7 — 13 rows 

 of alternately long and short cells. 



Conceptacula big ; slightly prominent, subimmersed in the frond. Diameter of conceptacula 

 from 300 rj. to 1 mm. Tetraspores from 90, 120 to 160 p. long. 



Amphiroa ephedraea is on account of its size one of the most easily known Amphiroae. 

 Small or dwarf specimens may give some trouble, but the structure of the node is a ready 

 help to recognise the species. The whole central strand and the whole cortical layer take part 

 in its formation, and the branching does not always take place at the node, but sometimes a 

 little below it. The cells constituting the node are short when the node is young, but increase 

 in length for a long time; I found cells at the base of the plant from 160 — 190 rj. long. I do not 

 think however that the number of cell-rows increases in any node ; I believe these to remain 

 the same in each node and not to change from the moment the node is formed. The 

 conceptacula and tetraspores of A. ephedraea are the biggest I have seen in this genus. In 

 longitudinal sections the conceptacula are seen to be immersed in the frond though, on account 

 of their size, they rise also above the frond. 



In Kützing's herbarium is a specimen called A. linearis Kützing from Senegambia 

 which I think is a stunted form of A. ephedraea. The nodes are like those of this alga only 

 rather short, and the top joints are a little flattened as in A. Beauvoisii Lamx. [exilis Harv.). 

 The material at my disposal is however far too little to allow me to express myself with more 

 certainty. It is highly desirable that naturalists should collect Amphiroa in vvell-grown specimens 

 to enlighten the study of these variable plants. 



7. Amphiroa eanaliculata von Martens. PI. XVI, hg. 9 — 12. 



Von Martens. Die Preussische Expedition nach Ost-Asien. Bot. Theil. Die Tange 1866, p. 28. 

 Yendo. Corallinae verae Japonicae Tokyo, 1902. 



Stat. 33. Pidjot Bay. Island of Lombok. 



Stat. 34. Bay of Labuan-Pandan. Island of Lombok. 



Fronds articulated, spreading over the substratum, branching dichotomously, branches 

 much diverging; joints broad, winged ; upper side convex, under side canaliculate with a 

 prominent midrib. Adventitious branches rare. Froncls consisting of central strand and cortical 

 layer. Central strand forms the prominent midrib and also the node and is built up of 4 or 5 

 rows of long cells 80 — 90 ij. foliowed by a row of short cells ± 28 p. ; cortical layer strongly 

 developed forms also the wings of the joints which are turned downward and sometimes meet 

 and coalesce. Node consists of central strand and a portion of the cortical layer which grows 

 in thickness with the thickness of the joints ; conceptacula on both sides of the joint, overgrown 

 by the cortical tissue. Diameter 320 — 360 \j,. Height of tetraspores 80 p.. 



A. eanaliculata is a very characteristic plant with its thick broad joints, which have a 

 very distinct midrib along the canaliculate under side of the joint. The node is the continuation 

 of the central strand, that divides dichotomously at the joint, and is surrounded by many 

 layers of cortical tissue. The non-calcified tissue of the node has its greatest development at 



SIBOGA-EXPEDITIE LXI. 



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