52 ECTOCARPACE^;. 



the filaments." Carm. Alg. Ap. ined.; Harv. in Hook. I. c. 

 p. 391. 



" On a thin purplish crust (Hildenbrantia rubra ?) which covers the peb- 

 bles at the half-tide level. The parasite is so much of the colour of the 

 crust that it requires a microscope to detect it." Capt. Carmichael. I 

 have never seen this plant. 



ORDER VI. ECTOCARPACE^. 



Ectocarpeae, C. Ag. Spec. Alg. vol. ii. p. 9, (excl. gen.) 

 Harv. Man. p. 36. Ectocarpese and Sphacelarieae, J. Ag. 

 Alg. Medit. p. 26. Sp. Alg. i. p. 627. Dne. Ess. p. 

 3342. Kulz. Phyc. Gen. pp. 287, 291. Ectocarpidas (in 

 part) and Sphacelaridse, Lindl. Veg. King. p. 22. 



DIAGNOSIS. Olive-coloured, articulated, filiform seaweeds, 

 whose spores are (generally) external, attached to the jointed 

 ramuli. 



NATURAL CHARACTER. Root generally a small disk, which 

 is occasionally coated with woolly fibres. Frond filiform 

 and slender (in technical language, filamentous), more or less 

 conspicuously articulated, each articulation composed either 

 of several cells disposed in a ring round an axis, or of a 

 single cell, in which latter case the frond is a filament, 

 formed of a series of simple cells, placed end to end, and 

 strung together. In some of the higher forms (Cladostephus 

 and some Sphacelaria] the main stem and the larger branches 

 are inarticulate, formed of a multitude of minute cells, the 

 central ones of which are frequently four-sided, closely com- 

 pacted together into a firm, somewhat horny, rigid substance. 

 The frond is rarely unbranched ; very generally it is exces- 

 sively divided, the branches disposed differently in different 

 genera. In Cladostephus the branchlets are whorled round 

 the stem and branches, and deciduous at the close of each 

 season. In Sphacelaria the whole frond is distichous, the 

 lesser divisions being repeatedly pinnate, and in this genus 

 also, a portion of the smaller ramuli appears to be deciduous. 

 In Ectocarpus the stem is sometimes, but rarely, simple ; 

 sometimes branched in a subdichotomous manner; but in 

 the majority of cases it is distichous, the branches being 

 either alternate or opposite, usually rather distant one from 

 another ; but sometimes closely pinnated, and occasionally 

 secund and pectinated. In one or two instances the thread- 

 like fronds are bundled together into ropes, which, branching 



