Irish Moss - perennial, algae, Jamaican drink, but not a true moss

Sorry to break it on St. Patrick's Day, but any plant or algae called Irish Moss is not a true moss, and may not even be indigenous to Ireland. Indeed, there are many mosses in Ireland, and the color green found in many mosses evokes thoughts of Ireland, but there is no true moss (bryophyte) by the name of "Irish Moss." To explore any loose association between a true moss and a mislabeled plant, let's look at two examples of "Irish Moss."

Sagina subulata - Irish Moss

Sagina subulata
Sagina subulata is a small, vascular perennial plant, which is referred to as Irish Moss, and also as Scotch Moss or Scottish Moss.  Despite the Celtic reference, this plant is not a true moss.  However, like many mosses, it is a tiny plant and makes a nice, low-growing ground cover that provides a shock of green in any garden setting.



Carrageen moss

Chondrus crispus

Chondrus crispus is a species of red algae that is often referred to as carrageen moss (Irish carraigín, "little rock") or Irish Moss.  It is used as a thickener and stabilizer in drinks and food and a clarifying agent in beer (what a relief on St. Patrick's Day).  It will form a jelly when boiled, and like many true mosses, the jelly substance can hold 20 to 100 times its weight in water.  Mosses, the first terrestrial plants, are regarded as descendants of algae and exhibit many of the same preferences for water and water retention. And, the "leaves" of Chondrus crispus certainly resemble a leafy moss.

There is a Jamaican drink called "Irish Moss" (go figure?) which calls for Irish Moss (the algae) as an ingredient!  The "moss" is boiled for an hour, but then discarded before the beverage is consumed.





For more information on how mosses are named and classified (taxonomy) and common misnomers (there are plenty more), check back for future "Moss Misnomer" postings. Also, sometime within the next month or so, there will be a posting called "Edible or Not?" which will explore the edibility of mosses. Until then, enjoy St. Patrick's Day and look out for moss and algae in your beer.