176 PHENOGAMS AND CKYPTOGAMS 



325. It happens that the spores of seed -bearing plants 

 are borne amongst a mass of specially developed leaves 

 known as flowers : therefore these plants have been known 

 as the floivering plants. Some of the leaves are devel- 

 oped as envelopes (calyx, corolla), and others as spore- 

 bearing parts, or sporophylls (stamens, pistils). But the 

 spores of the lower plants, as of ferns and mosses, may 

 also be borne in specially developed foliage, so that the 

 line of demarcation between flowering plants and flower- 

 less plants is not so definite as was once supposed. The 

 one definite distinction between these two classes of plants 

 is the fact that one class produces seeds and the other 

 does not. The seed -plants are now often called sperma- 

 phytes, but there is no single coordinate term to set off 

 those which do not bear seeds. It is quite as well, for 

 popular purposes, to use the old terms, phenogams for 

 the seed -bearing plants and cryptogams for the others. 

 These terms have been objected to in recent years be- 

 cause their etymology does not express literal facts (plie- 

 nogam refers to the fact that the flowers are showy, and 

 cryptogam to the fact that the parts are hidden), but the 

 terms represent distinct ideas in classification. Nearly 

 every word in the language has grown away from its 

 etymology. The cryptogams include three great series 

 of plants the Thallophytes or algae, lichens and fungi, 

 the Bryophytes or moss -like plants, the Pteridophytes or 

 fern -like plants. In each of these series there are many 

 families. See Chapter XXV. 



REVIEW. What is a spore? Describe the appearance of some 

 fern plant which you have studied. What are the spores and spor- 

 angia? What is a sorus? Indusium? What grows from the spore? 

 How does the new "fern" plant arise? What is meant by the phrase 

 "alternation of generations"? Define gametophyte and sporophyte. 

 Describe the alternation in flowering plants. Explain the flower from 

 this point of view. What is the significance of the word sperma- 

 phyte? Contrast phenogam and cryptogam. 



