194 Minnesota Plant Life. 



Woods and Rainy lake. Their leaves, like those of the red 

 cedar, lap over each other, are short and sli,<;iitly pointed. They 

 stand in four rows, j^'iving' the branch upon wliicli the}' arc home 

 a square appearance. 



Characters of lower seed plants. There are a number of 

 features in which the yews and pines agree. The seeds of each 

 are produced in such a way that when young- the ])ollen spores 

 may fall close to their ends, so that the only tissues through 

 which the pollen-tube must grow to reach the female plant are 

 the cells of the spore-case that surrounds the large-spore in 

 which the female ])lant is situated. For this reason the lower 

 seed-plants are sometimes called the naked-seeded plants. While 

 the seeds are maturing they are enclosed, except in the ground 

 hemlock, (piite as truly as are those of higher forms. In the 

 juniper-berry, for illustration, when it is full grown, the scales 

 which constitute the little fleshy cone are blended at their edges 

 in such a manner that the seeds are entirely enclosed and can- 

 not at all be termed naked. In the pines proper, too, the young 

 cones appress their scales so tightly that the seeds are quite 

 as effectually protected as they would l)e in the closed fruits of 

 higher types. At first, how'ever, even in the junipers, the scales 

 of the immature cone are open and it is ])ossible for pollen- 

 spores to fall between them, thus reaching the ends of the young 

 seeds growing upon their inner surfaces. 



A character in which the lower seed-plants all agree is the 

 production of albumen in the seed before the egg of the female 

 is fecundated b\- the sperm-nucleus of the ])ollen-tube. In the 

 higher seed-plants the albumen of the seed, w hen present does 

 not form until the egg which is to jjroduce the embryo has re- 

 ceived its fecundation. The albumen of the seed may be re- 

 garded as the body of the female ])lant and the young embryo 

 nurses ui)on it during its life within the seed just as the young 

 spore-producing plants of a liverwort or moss nurse iii)on the 

 vegetatix'e body of the sexual plants of tlicir species. 



In still another respect the lower seed-j)lants agree and dit'fer 

 from all the higher seed-plants. In tlieni. on the l)od\ of the 

 female ])lanl produced within the large-sj)ore, true egg-organs 

 are forme(l. each enclosing an egg and pro\ided with a short 

 neck the end of which is near the inner surface of the si)ore- 



