Alaria |
|
| 1. | Stipe more than 15 cm long; distal end of sporophyll sterile | Alaria fragilis |
| 1. | Stipe less than 15 cm long; sorus covers sporophyll | 2 |
|
| 2. | Length of sporophylls more than five times breadth; mid-intertidal | 4 |
| 2. | Length of sporophylls less than five times breadth; low intertidal or subtidal | 3 |
|
| 3. | Sporophylls thicker than the blade; with asymmetrical cordate base | Alaria marginata |
| 3. | Sporophyll about as thick as blade; with symmetrical base | Alaria taeniata |
|
| 4. | Sporophyll petioles 3 mm or more in diameter | Alaria crispa |
| 4. | Sporophyll petioles approximately 1 mm in diameter | Alaria nana |
|
Desmarestia |
|
| 1. | Blade wide, orbicular, unbranched; one or more blades arising from short holdfast | Desmarestia tabacoides |
| 1. | Blades branched | 2 |
|
| 2. | Plants cylindrical (or slightly compressed) throughout | 3 |
| 2. | Plants flattened or ligulate, at least in part | 4 |
|
| 3. | Branching alternate | Desmarestia aculeata |
| 3. | Branching generally opposite | Desmarestia viridis |
|
| 4. | Plants terete or compressed in lower axes, ligulate above | Desmarestia latifrons |
| 4. | Plants ligulate throughout, with visible midrib | Desmarestia ligulata |
|
Ectocarpus |
|
| 1. | Plurilocular structures uniseriate and multiseriate on both creeping and upright filaments | Ectocarpus commensalis |
| 1. | Plurilocular structures multiseriate (except in cases of abnormality) on erect filaments only | 2 |
|
| 2. | Plants usually less than 5 cm high | 3 |
| 2. | Plants over 5 cm high | 4 |
|
| 3. | Plant densely corticated below; usually more than 3mm tall; | Ectocarpus corticulatus |
| 3. | Plant not corticated; 1 -2 mm tall | Ectocarpus simulans |
|
| 4. | Terminal ramuli long and acute | Ectocarpus acutus |
| 4. | Terminal ramuli long and attenuated | Ectocarpus siliculosus |
|
|
|
|
|
Laminaria |
|
| 1. | Holdfast discoid | 2 |
| 1. | Holdfast of distinct, branched haptera | 3 |
|
| 2. | Mucilage ducts absent from blade; throughout local area | Laminaria ephemera |
| 2. | Mucilage ducts present in blade; not reported south of northern British Columbia | Laminaria yezoensis |
|
| 3. | Numerous stipes arising from rhizoidal holdfast system | Laminaria sinclairii (in part) |
| 3. | One stipe arising from each holdfast | 4 |
|
| 4. | Mucilage ducts absent from stipe | 5 |
| 4. | Mucilage ducts present in stipe | 7 |
|
| 5. | Stipe complanate, usually longer than 30 cm | Laminaria complanata |
| 5. | Stipe terete, usually shorter than 20 cm | 6 |
|
| 6. | Bullae, when present, in two rows parallel to margin of blade | Laminaria saccharina |
| 6. | Bullae covering entire blade | Laminaria farlowii |
|
| 7. | Stipe terete throughout; blade deeply dissected into many narrow, uniform segments | Laminaria setchellii |
| 7. | Stipe often slightly to extensively complanate | 8 |
|
| 8. | Blade often bullate; generally dissected, of few segments varying in width and length | Laminaria bongardiana |
| 8. | Blade always smooth; not dissected though they may be torn | Laminaria sinclairii (in part) |
|
|
Myrionema |
|
| 1. | Upright filaments with several discoid plastids in each cell | Myrionema strangulans |
| 1. | Upright filaments with one or two plastids per cell | 2 |
|
| 2. | Discs less than 1 mm in diameter; plurangia present; on Phyllospadix | Myrionema balticum |
| 2. | Discs up to 2 mm in diameter; unangia present; on laminarians | Myrionema corunnae |
|
Ralfsia |
|
| 1. | Plants with prominently overlapping lobes or layers | Ralfsia fungiformis |
| 1. | Without prominent overlapping lobes or layers | 2 |
| 2. | Crusts fleshy or coriaceous, cells of upper horizontal layers 3 to 4 times long as wide | Ralfsia hesperia |
| 2. | Crusts firm, not fleshy or coriaceous, cell of horizontal layers not over twice as long as wide | Ralfsia pacifica |
|
| See also the sporophyte of Petalonia fascia (=Ralfsia californica), which is dark brown and possesses unilocular structures only. |
|
|
Sphacelaria |
|
| 1. | Branching regularly pinnate | 3 |
| 1. | Branching irregular, sometimes sparse; basal discs small, often connected by creeping filaments | 2 |
|
| 2. | Zones of 4- 6 longitudinal cells in lateral view; propagules absent | Sphacelaria racemosa |
| 2. | Zones of 1- 4 longitudinal cells in lateral view; propagules present | Sphacelaria rigidula |
|
| 3. | Lateral branchlets longer from base to apex, giving a pyramidal appearance | Sphacelaria norrisii |
| 3. | Lateral branchlets of same length, so branch has straight sided appearance | Sphacelaria plumigera |