65 



more slender in the dimensions of its fïlaments (fig. 150), has no tenacula, and being mono- 

 siphonous has of course no affinity with Bood/ca, which is a genus of Valoniaceae. The real 

 affinity of Boodleopsis has still to be found. 



The principal character of the genus is the abundant ramification of its branches (fig. 150). 

 This ramification consists of a much repeated, divaricate dichotomy in alternating planes, varied 

 frequently with trichotomies (fig. 152) or rarely verticillate nodes (fig. 151). This ramification 

 is so abundant as to rencler inconspicuous the humble little-branched main axis (figs. 148, 

 149). The much-branched, short, straight, slender ramuli are extensively and loosely intricated 

 (figs. 147, 150), somewhat as in the capitulum of Penicillus pyriformis or the verticils of 

 Tydemania expeditionis . But there the similarity with the tvvo calcified plants ends. The charac- 

 ters of Boodleopsis are such as to prevent its inclusion in any previously described genus of 

 Codiaceae. It is a humble, pulvinate little plant, easily overlooked. Its loose structure permits of 

 a ready percolation of water, much as in the diaphanous species of Rhipilia. 



In connection with the inconspicuous primary filament or main axis mentioned above, 

 it is interesting to compare fig. 180, n" 3, in Oltmanns' Morphologie und Biologie der Algen, 

 Vol. I. 1904, p. 293, where it is shown that Udotea Desfontainii {Flabcllaria petiolata of the 

 present memoir) possesses a very similar horizontal primary axis. 



10. Tydemania Weber van Bosse. 

 ( Fi g s - I53—I55)- 



Ann. Jard. Bot. Buitenzorg 2? sér. vol. II. 1901. p. 139; Wille in Engler und Prantl naturl. 

 Pflanzenfam. I. Teil, 2. Abteil. Nachtrage 1910. p. 129, fig. 6j. 



Plant large or minute, calcified, composed of a simple or branched, monosiphonous, 

 cylindric, or here and there subtorulose main axis, prostrate and sparsely rooting below and 

 bearing, at short irregular intervals, flabella supported on very short or longer stipites ; in the 

 type-species the main axis ascends and bears at regular intervals glomeruli, composed of laxly 

 interwoven ramelli. Fructification unknown. 



The flabella of Tydemania recall the simpler species of Udotea, namely U . javensis 

 and U. glaucescens and the flabellules of Rhipocephalns phoenix\ but are readily distinguishecl, 

 even when detached from the main axis, by the bead-like basal articuli (see figs. 154, 155) 

 and stipites. 



The glomeruli (fig. 153) on the other hand are to be compared with small capitula 

 of Penicillus, but differ in the intricate entanglement of the constituent ramelli caused by the 

 alternating and divaricate branching (fig. 153a), the dichotomies often enclosing more than a 

 right angle. A similar lax entanglement of repeatedly branching ramelli is found in Boodleopsis 

 (fig. 150), which however differs totally in its humble pulvinate habit, slender filaments and 

 lack of calcification. 



The affinities of Tydemania are with Penicillus on the one hand and with Rkipocepkalus 

 and Udotea on the other. We regard these grenera as all arising from a cornmon ancestor, 

 the stages of the descent being lost, though partly indicated by Espera and Tydemania. 



SIBOGA-EXPEDITIE I.XII. 9 



