These are mosses in their sporophyte or seed-bearing stage. Each of the green capsules are about 1.5mm thick and 4mm long and contain thousands of spores that will be released to start a new generation. This process is called the alternation of generations. Moss life cycles alternate between two distinct phases, sexual and asexual, each phase producing the other. The sexual phase is called gametophyte generation which will produce gametes or sex cells, while the asexual phase in turn will produce spores and is called sporophyte generation. In this sporophyte phase, a diploid plant body grows and finally gives rise to spores by means of meiosis (a process producing cells genetically unique from the parent). These spores are haploid, and will then undergo mitosis (a process producing genetically identical daughter cells), and produce haploid multicellular bodies with a single set of chromosomes called gametophytes. These capsules are diploid.

California lace fern
Aspidotis californica
Pteridaceae