Name: Punctaria plantaginea
Family: Chordariaceae
Collection Date: 15 September 2011
Location: Nantasket Beach, Massachusetts
Collector: Dr. Matthew Hils
Key Used: Dawson, E.Y. (1956). How to Know the Seaweeds. Dubuque: WM. C. Brown Company Publishers.
Pictured-Key to the Common Genera of Macroscopic Marine Algae of the United States
1b. Thallus consisting of more than one cell, or if coenocytic, at least not sub spherical in form … 2
2b. Thallus not calcareous … 3
3b. Thallus without hollow structures or parts (except sometimes the coarse stipe, as in Postelsia) … 4
4b. Thallus not crustose or net-like, free except for one or more basal attachments … 5
5b. Thallus of various form and structure, but consisting neither of one or more branches or unbranched uniseriate filaments, nor of a branches, free, essentially cylindrical filament without cellular septations … 6
6b. Thallus cylindrical or flattened; if membranous, with more than two layers of cells at the margins … 7
7a. Vegetative portions of thallus dominantly compressed, flattened, or complanate … 125
125b. Thallus without a midrib, median stripe or veins … 143
143b. Blade not saucer-shaped … 144
144b. Thallus simple or variously branched; if simple and broadly expanded, at least not fan-shaped; if branched and dichotomous or subdichotomous, any resulting fan-like form arises from the branching; color brownish, greenish, or reddish …147
147a. Plants essentially simple, consisting of one or more entire or lobed blades; branching mainly restricted to basal region although sometimes the blades proliferous from the flattened surfaces (Caulerpa), or from the margins (Gigartina; Grateloupis) … 148
148b. Holdfasts simple and discoid, or of coarse hapteres, without penetrating rhizoids … 149
149b. Blades estipitate, or form a very short stipe … 151
151b. Surface of blades smooth … 152
152a. Thallus dark brown or yellowish-brown (as opposed to reddish, purplish or greenish) … 153
153b. Thallus thin, of few cell layers, the surface cells little different from those of the inner layers … Punctaria
Description:
“Plants in the form of broadly lanceolate blades arising from small basal disks, the stalks short, the blades with tapered bases, obovate-lanceolate, often mechanically split or truncate toward the tip, in length usually less than 2 dm., but to 6.5 dm., flat or very little undulate at the margin; texture somewhat firm, ever coriaceous, 4-7 cells and 110-225 µ thick, cell membranes rather heavy, surface cells 15-40 µ diam.; plurilocular gametangia somewhat increasing the thickness of the thallus, to as much as 50 percent, their lower parts sunken in the surface layer, oblong or obovoid, 30-48 µ long, 20-34 µ diam.; unilocular sporangia (?) nearly globose, 32-48 µ diam” (Taylor, 1957) .
Links:
References:
Dawson, E. Y. (1956). How to Know the Seaweeds . Dubuque: WM. C. Brown Company Publishers .
Taylor, W. R. (1957). Marine Algae of the Northeastern Coast of North America . Ann Arbor : The University of Michigan .
Figure 1: Close up of Punctaria plantaginea
Figure 1: Close up of Punctaria plantaginea
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