s A Field Guide to the British Seaweeds - NMBAQC

11. Plant black and wiry with disc-like holdfast, narrow branching very irregular
and often found in sandy environments Ahnfeltia plicata
11. Plant elastic, long and straggly, branching very irregular sometimes becoming
bushy, cartilaginous and firm Gracilaria gracilis
Group D
1. Plant polysiphonous………………………………………………………..…2
1. Plant not polysiphonous………………………………………………..……..4
2. Main branches polysiphonous, smaller branches monosiphonous and
numerous, appearing tufted Heterosiphonia plumosa
2. Plant polysiphonous throughout………………………………...…………….3
3. Plant found growing epiphytically on Ascophyllum species often quite course
and tufted in texture Polysiphonia lanosa
3. Plant with 12-20 siphons, lower, older filaments of plant covered with small
cells (corticate), branching irregular with upper parts of plants more densely
covered, generally dark brown or black in colour Polysiphonia fucoides
3. Not as above Polysiphonia sp.
4. Plant appearing banded, dichotomously branched with terminal branches
generally in-rolled…………………………………………………………..…5
4. Plant not appearing as above………………………………………………..…6
5. Plant almost or completely covered in small cells (corticate), plants quite
variable, irregularly dichotomous, terminal branches tightly in-rolled or
straight, very common Ceramium nodulosum
5. Plant with multicellular spines present on the outside of filaments, not
completely corticate, dichotomously branched and terminal branches strongly
in-rolled Ceramium shuttleworthianum
5. Plants not as above Ceramium sp.
Reduced species list identification guide as required by the Water Framework Directive 36