Minnesota Plant Life= 



159 



as well as along spore-producing lines, so the sexual plant — the 

 one developed from the spore — has become reduced and is sim- 

 pler, smaller and less important than the sexual plants of liver- 

 worts or mosses. 



Different kinds of club-mosses in Minnesota. The different 

 kinds of club-mosses in Minnesota are distinguished by differ- 

 ent habits of branching, different shapes of leaves and the vary- 

 ing distinctness with which the cone-area is blocked out in the 

 general plant-body. Some, as the tree-like club-moss or ground- 

 pine, have erect stems with subsidiary branches like those of a 



pine. Another kind has the leaves 

 flattened in a peculiar way like the 

 leaves of the white cedar. In still 

 another species the plant-body 

 branches loosely and trails over the 

 ground, while in yet another the 

 stem forks, and tufts 

 of branches are pro- 

 duced, reminding one 

 a little of the true- 



mosses. 



The 



mosses. 



rock-club- 



The smaller 



Fig. 51. Smaller club-moss. To the left a plant with three 

 cones, next a single cone dissected to show the spore 

 cases, next a single large-spore-case with four spores 

 revealed, and on the right a small-spore-case with the 

 small spores sifting out. After Atkinson. 



club-mosses or rock- 

 club-mosses are pretty abundant throughout the state wher- 

 ever dry rocks or rocky hills occur. The leaves in the com- 

 mon species are pressed close together along the stem and 

 each has at the end a white bristling hair, giving a hoary ap- 

 pearance to the whole plant. The cone-areas are not so dis- 

 tinctly different in appearance from the rest of the plant-body 

 as in the larger club-mosses. The great peculiarity of these 

 plants is their production of two kinds of spores. In some of 

 their spore-cases two hundred or more small spores will be 

 produced, each somewhat pyramid-shaped, while in other spore- 

 cases — perhaps in the very same cone — there will be produced 

 four much larger spores with variously marked walls and of a 

 generally spherical shape. When a smaller spore germinates, 

 it produces a Httle male plant so insignificant that it never comes 

 outside its spore-wall, but forms and matures altogether within. 

 This little male creature produces a few sperm cells. \\'hen 



