Ruth is again responsible for today’s write-up:
I’m in a bryophytes course this term, and as I harvest knowledge from some of the most reputable human sources in the world I will be passing it on to you, the lucky reader. Bryophytes (mosses, hornworts and liverworts) are a group of plants that people rarely consider. In an urban environment, their presence is easily unnoticed unless they have claimed your front door or stone walkway as their own.
Without a microscope, this species looks like little green cushions or tufts on rock surfaces, preferably granite. They get a lot more interesting when put under a microscope or electron micrograph. This picture is one my lab partner Carolina Chanis took of Andreaea nivalis leaves under 10x magnification. Thanks Caro!
The Andreaeidae are commonly referred to as the granite mosses or lantern mosses. The lantern reference is due to the dried sporangium shape. Thanks to Shona Ellis for putting together this course website and supplying some awesome electron micrograph pictures of the sporangium of Andreaea nivalis as a complement to today’s photograph of a leaf.
The gametophyte, or the haploid generation responsible for growth, is the green leafy part we typically associate with mosses, though in this species it can even be red-brown or black. When mature and ready to disperse spores, the sporangium dehisces along four or five lines to allow wind and water access. Also, the columella, or point in the centre of the sporangium, depresses to push out the sporangium wall and allow dehiscence. The genus Andreaea and Andreaeobryum are the only two genera within the subclass Andreaeideae. Members of the Andreaeidae tend to be found in mountainous and arctic regions of the world.
I hope you are intrigued as I have many more pictures, and I am becoming a wealth of information on these little cuties (midterm approaching).