30 MOSSES WITH A HAND-LENS 



fall in a storm strike the upper surface (Vide " Goebel Organ- 

 ograhpy," Pt. I, p. 237, Balfour's translation) and send the spores 

 out in little puffs, sometimes to a height of two inches. This 

 effect can be produced by tapping a mature deoperculate capsule 

 lightly upon the upper side. Note how the nozzle-like peristome 

 is pointed straight up so that the spores are fired as high as 

 possible from the miniature powder gun. It seems probable that 

 the wind which accompanies summer storms serves to further 

 disperse these spores and that the ejection of the spores ceases 

 after the capsules are well wetted; but this needs further in- 

 vestigation. 



It also seems perfectly sure that other agencies than rain- 

 drops will serve to force the spores out of Webera and Bux- 

 baumia's " powder guns ;'' for example, the impact of the feet 

 of large insects and other small animals. Perhaps the jet of 

 spores may leave some clinging to the hair or fur of the animals 

 which discharge them, and through that means they may be 

 carried for considerable distances. 



Family 6. FisSIDENTACEAE. The Fissidens Family. 



HIS is one of the most natural and easily recognized 

 of the families of mosses. Only one genus, Fissidens, 

 is common and the characters of this genus are the 

 characters of the family for the most part. 



FISSIDENS. 



The leaves of Fissidens are in two rows on opposite sides of 

 the stem and both rows lie in the same plane, giving the plants 

 a peculiar flattened appearance like a Hepatics. The leaves are 

 vertically placed and apparently split along the basal portion of 

 the upper margin so as to clasp the stem and the base of the leaf 

 next above. 



The leaf-cells are small, rounded or hexagonal. The sporophyte 



Plate VII. Fissidens adiantoides. (From Bry. Eur.). 

 5. Plant natural size. 8. Perigonial leaf. g-ii. Leaves, ii x. Cross 

 sections of the lower part of leaf, ii a. Apex showing border of lighter 

 cells. 



