1 2 



the margin, subparallel, congested, pluriseriately arranged, the layers of filaments crossing 

 obliquely, dichotomously but inconspicuously branched, normally unevenly constricted above the 

 clichotomy, bearing numerous unilateral, short, simple or bifid (rarely trifïd), sessile (rarely 

 pedicellate), pointed appendages. 



Filaments of stipes bearing lateral appendages, 2 — 4 times dichotomous and terminated 

 by dactyline tapering acute apices, which are approximated together to form the cortex of the 

 stipes. [Figs. 10, 11, 54]. 



The type of U. Palmetta Decne. is preserved in the Paris Herbarium (tig. 10), but 

 there is no information to shew where the specimen was gathered. And since Decaisne gives 

 none in his original description, there is unfortunately no clue as to the original home of the 

 type. Decaisne's specimen was for some years the only representative of this species so far 

 as we can ascertain. The home of U. palmetta remained therefore a mystery until the collec- 

 tions of Mr. Stanley Gardiner yielded fresh examples, which indicate without doubt that the 

 original locality of the type was situated in the western Indian Ocean, possibly indeed at 

 Galega Island. We have discussed this question in a paper in Trans. Linn. Soc. (Bot.) VII. 

 1908. p. 175. 



The main filaments in the frond of U. palmetta are sometimes disposed in two layers 

 only, but sometimes in as many as three to five layers. 



The nearest ally of U. palmetta is U. spinulosa Howe, a West Indian species, which 

 it resembles in having unilaterally situated, spinose appendages on its frond-filaments. It differs 

 however from that species in having the frond-filaments about half as thick as in U. spinulosa, 

 the lateral appendages usually sessile and simple or forked or trifid (rarely stalked and never 

 pluri-spinose) (lig. 11), and the supra-dichotomial constrictions markedly uneven. 



The West Indian U. vertieillosa differs in having the lateral appendages disposed 

 around the upper frond-filaments in dense subverticils (fig. 23 a). 



U. indica has unilateral appendages on the superricial filaments of the frond ; but they 

 are short, blunt, peltate or truncate (fig. 53). As in that species and in U. spinulosa, so also 

 in U. palmetta, the lateral appendages are situated only on the external surface of the super- 

 ricial filaments, and function as "windows" (see pp. 5 and 103); they are absent from the 

 inner surfaces where the filaments touch one another. 



Decaisne's original description of U. palmetta in his Mémoire sur les Corallines 

 (1. c.) was short and insufficiënt and omitted all mention of the lateral appendages of the 

 filaments, though they had already been figured in his Classification des algues (1. c.) and 

 mentioned in his short obscure note (1. c. p. 380) explanatory of the figure, where he describes 

 the main filaments as "Cellules dentées, qui par leur enchevêtrement, constituent toute la 

 "partie inférieure de la plante ; dans leur premier age, ces cellules sont presque cylindriques". 

 This passage and the figure seem to have been entirely overlooked. Consequently Kützing, 

 J. G. Agardii and others, who have never examined the type-specimen, have failed to form 

 a true conception of this species. They have confused it on the one hand with some Australian 

 specimens which we include under U. orientalis, and on the other with a plant from the 



