Specimen #4: Bladder Wrack

Name:  Fucus vesiculosus,  Linnaeus – Bladder Wrack

Family:  Fucaceae

Collection Date: 15 September 2011 

Location: Nantasket Beach, Massachusetts 

Collector: Dr. Matthew Hils

Key Used: Taylor, W. R. (1957). Marine Algae of the Northeastern Coast of North America . Ann Arbor : The University of Michigan .

Key to the Orders of the Marine Algae

1. Chlorophyll masked by accessory pigments … 3

3. Accessory pigments imparting a brown color; reproduction at some stage typically involving flagellate cells … 10

10. If filamentous, not polysiphonous, though often pluriseriate … 12

12. Massive, cylindrical, or phylloid, or slender but pluriseriate, or reduced types … 13

13. Filamentous structure lacking, obscured, or only shown in evanescent plant parts … 14

14. Sporophyte lacking free assimilators … 15

15. Gametophyte reduced to cytological phases; sporophyte massive and branched … Fucales p. 188

Key to Families

1.  Axes subterete, to alate with a midrib, but not foliar; vesicles if present intercalary … Fucaceae, p. 189

Key to Genera

1.  Branches strap-shapes at least above, with a thickened midrib … Fucus, p. 189

Key to Species

1. Margin not serrate, though often frayed … 2

2. Plants larger, regulary exceeding 15 cm … 4

4. Receptacles swollen … 6

6. Receptacles not ridged, though sometimes the margin angled when young; blades with usually paired vesicles; sexes in different plants …. F. vesiculosus, p. 192 

Description:

“Plants often large, generally 3-9 dm. tall, attached by an irregular, lobed holdfast; branching usually dichotomous or a little irregular, often proliferous below, the branches above strap-shaped, about 10-15 mm. wide, with a marked midrib throughout, but below denuded of the thin margins; scattered cryptostomata and vesicles each side of the midrib, or three together at a fork; receptacles terminal on the branches, single, paried, or forked, broadly lanceolate to obovate, usually 1.5-2.5 cm. long; sexes in different individuals, the antheridial conceptacles orange when the receptacles are opened, while the oogonial conceptacles are olive-green” (Taylor, 1957).

Links: 

http://www.rxlist.com/bladderwrack/supplements.htm

http://www.puritan.com/vf/healthnotes/hn_live/Herb/Bladderwrack.htm

Figure 1: Fucus vesiculosus, otherwise known as Bladder Wrack

References:

Taylor, W. R. (1957). Marine Algae of the Northeastern Coast of North America . Ann Arbor : The University of Michigan .