Griffithsia globulifera Harvey ex Kützing (A)

Plants sparsely to richly branched tufts to 10 cm tall, light pink to yellow-pink in colour, and slippery in consistency (Image A). Branching is typically dichotomous and the axes are uniseriate lacking any cortical development (Image B). Cells are swelled at their tips, but rounded and constricted at their base imparting a jointed or articulated look where they meet, ranging in size (mid thallus toward the tips) from 100-250 µm wide and 500-1500 µm long and being visible to the unaided eye (Image B). Tetrasporophytes  produce whorls of single-cell pedicels, each bearing 1-3 spherical tetrahedral tetrasporangia in various stages of development (45-90 µm when mature) and interspersed with short involucral filaments (Image C).

We have only a few genetically verified records ranging from RI to MA, and then again in around the Northumberland Strait. However, in these areas this is a common species in the shallow subtidal to 10 m growing on rock and other algae. Appears to be a summer annual, but reportedly regenerates from perennial basal filaments that persist through the winter (Bird & McLachlan 1992).

 

Image A. Individual collected in the drift from the beach to the east of Parlee Park Beach, NB (GWS044431).

Image B. Branching dichotomous, the axes uniseriate and lacking cortication. Cells mid thallus are large enough to be seen by the unaided eye (GWS044431).

Image C. Fertile node on a tetrasporophyte with pedicel cells (arrows) bearing 1-3 tetrasporangia in various stages of development, these interspersed among short involucral filaments. Mature tetrasporangium with tetrahedral division pattern (double arrow) (subtidal (3 m) on rock, Pointe du Chêne, Northumberland Strait, NB; GWS39093; fixed in formaldehyde, aniline stained).