Thank you to Courtnay H, aka Seaweed Lady@Flickr, for sharing today's photograph (original image via BPotD Flickr Group Pool. If you love the sea and plants (like me), you certainly should view Courtnay's photographs on Flickr.

Courtnay suggests the following link to accompany her photograph: Codium fragile subsp. tomentosoides via Algaebase. If you visit that page, the word “weed” is used (Courtnay calls this photograph “beautiful invader”); indeed, this species is listed in the Global Invasive Species Database, with a comprehensive list of common names: dead man's fingers, green fleece, green sea fingers, oyster thief or Sputnik weed. Originally from Japan, it is now found in many temperate waters worldwide, its dispersal due to “shellfish aquaculture, recreational boating, and transport on ship hulls”.

The common name of oyster thief is due to this alga's tendency to proliferate in shellfish beds, where it can smother the shellfish with its rapid growth and colonial expansion. Sputnik weed is, as you might guess, a fifty year old common name from eastern North America. The introduction of this species to eastern North American waters was first observed around the same time as the launch of the Soviet Union's satellites.