95 



conceptacula are sometimes very big, 410 u. in diameter, sometimes much smaller. I thought 

 their size might perhaps give a good speciiïc character but since I found on one joint concep- 

 tacula of 300 o. and others of 400 u, I feel doubtful as to the value of this character. I 

 believe that all the above given synonyms belong to A. anceps, or it might be that the plants 

 when studied in detail at the spot where they are growing, will reveal constant differences that 

 escape me now ; for the present I feel inclined to explain the existing differences in form of 

 joint etc. by influences of the environment. A. anceps is highly variable in its colour. Dried 

 specimens of very different hue have passed through my hands, but this cannot be considered 

 as a specific character. 



5. Amphiroa Bowerbankii Harv. PI. XIV, fig. 14 — 17. 



Harvey. Nereis Australis p. 97, tab. XXXVII. 



Kützing. Tab. Phyc. t. 8, tab. 50. (The little dots of calcareous tissue on the nodes are not 



given in the figure). 

 Areschoug in J. G. Agardh. Spec. Gen. et Ord. Alg. t. II, 185 1. 



Southcoast of Java. leg. Teysman. 



Fronds branching di- or trichotomously from broadened top of last joint, with adventitious 

 branches springing from the joint not from the node; joints at base of plant either cylindrical 

 or broad and flattened, more or less canaliculate with central strand protruding below, winged 

 with undulating border. Upper joints flattened, border slightly undulated or two-edged, in well- 

 grown specimens distinctly zonate. 



Central strand consisting of 2, 3, 4 rows of long cells 56 — 108 p. high, foliowed by a row 

 of short cells 8, 12, 40 ij, high. Cortical layer thicker than in A. anceps. Nodes appear as in 

 A. anceps in the broadened part of the last joint and consist of a non-calcified part of the central 

 strand and of the cortical layer adhering to it. The other calcified part of the central strand splits 

 as does also the cortical layer. From the uncalcihed cortical layer of the node spring forth 1 — 7 

 little dots of calcareous tissue, sometimes covering the node almost entirely. Conceptacula slightly 

 prominent or subimmersed in the cortical layer, diameter from 360 — 460 ij.. 



Amphiroa Bowerbankii is closely allied to A. anceps but it can be easily distinguished 

 from this latter alga. As a rule it is broader, its cortical layer thicker, its conceptacula less 

 prominent than in A. anceps, but the character by which it is most easily known are the nodes 

 which are characterized by little dots of calcareous tissue. These will sometimes fa.il, though as 

 a rule I believe, that on carefully searching a plant apparently without dots, one is almost 

 always sure to find at least a single dot, indicating the species to which the plant belongs. 

 The joints at the base, when they are not cylindrical, can be as broad as 1 cm. and these 

 broad joints have an outward likeness to the joints of A. canaliculata. I once thought that 

 plants with such broad joints, might be an intermediate form between A. Bowerbankii and 

 A. canaliculata and wrote in this sense to Mr. Vendo ') but specimens that I got later on 



1) K. Vkndo. Enumeration of corallinaceous algae hithevto known from Japan. — Bot. Mag. of Tokyo, vol. XVI, n» 189, 

 Nov. 1902, p. 6. 



