642 
IX. ALGiE. 
Tribe II. Laurenciese. Frond inarticulate , solid, tubular or septate ; surface-cells 
minute. Spore-threads simple or branched. Tetraspores irregularly scattered through 
the branchlets. 
* Frond hollow, full of fluid ; tube septate : septa close together 42. Champia. 
** Frond solid, cellular, flat or compressed ; branchlets obtuse or constricted at the base. 
Frond terete or compressed 43. Laurencia. 
Frond filiform, articulate 44. Chondria. 
Frond fiat, membranous 45. Cladhyjienia. 
*** Frond solid, cellular, cylindric or compressed ; branchlets distichous, subulate or 
setaceous or serrate. 
Frond decompound ; branches setaceous, subarticulate. Conceptacles 
scattered, on long stalks 46. Asparagopsis. 
Frond decompound ; branches subulate. Conceptacles sessile on 
the tips of the branches 47. Delisea. 
Frond decompound, serrate. Conceptacles terminal on the tips of 
branches 48. Ptilonia. 
b. Placenta on the base of a hollow conceptacle. Spores roundish or elliptic, in moniliform 
threads, all the cells of the spore-thread being changed into spores. 
Tribe III. Corallinese. Frond calcareous, its cells secreting carbonate of lime. 
Spore-threads separating into 4 spores. 
* Corallines. Frond branched, filiform, articulate. 
Conceptacles conical, on the disk of the articulations 49. Amphiroa. 
Conceptacles urceolate, terminal, smooth 50. Corallina. 
Conceptacles turbinate or urceolate, 2-4-horned 51. .Tania. 
** Nullipores. Frond crustaceous or foliaceous, inarticulate. 
Frond rigid, crust-like, or branching with the brauches stony . . 52. Melobesia. 
Tribe IV. Sphaerococcoidese. Frond cartilaginous or membranous. Spore-threads 
separating into many spores. 
* Delesseriese. Tetraspores divided into threes , disposed in definite sori. 
t Frond foliaceous, symmetrical , costate. 
Costa running through the frond 53. Delesseria. 
Costa slender, vanishing below and above 54. IIemineura. 
ft Frond foliaceous ; costa 0 or faint. 
55. Nitophyllum. 
** Spbasroeocceee. Tetraspores immersed in the cortical cells, divided cruciately or 
transversely . 
t Tetraspores transversely divided. 
§ Frond with a central articulate tube 56. Phacelocarpus. 
§§ Frond without a central tube. 
Frond of 2 strata of cellular tissue 57. Cali.iblf.pharis. 
Frond of 3 strata of cellular tissue 58. Sarcodia. 
ft Tetraspores cruciately divided ( unknown in Melanthalia). 
Frond ecostate, of two strata of tissue 59. Gracilaria. 
Frond dichotomously flabellate, of three strata of tissue .... 60. Melanthalia. 
