58 



PLANT LIFE. 



66. Protonema. — In its early stages tlie vegetative body 

 of the leafv li\'erttorts and tlie mosses is either a flat tlialliis, 

 similar to the m:iture form of the thallose li\'er\vorts, or a 

 branching filamentous body, called the proloiienia, almost 

 identical «'ith the f<irni of the filamentous alga;. U])on this 

 protonema the leafy shoot arises as a lateral bud, which soon 

 outstrijis it in growth and differentiates leaves. The proto- 

 nema may li\'e for some months, but generally pierishes after 

 having produced a few lealy plants. 



67. Sporophyte. — The non-sexual phase in the liverworts 

 and mosses has almost no vegetative functions, and a fuller 



Ftg. 72 — A^ Lull capsules nf nrjiiin ; frnm ttie ri^lit-liand nne Uie lid has fallen, 

 showing the teeth. Magnified 5 diani. Z>, four gametophyte shuocs of S/^lcicknuin 

 ain/'ultaceutn, bearing four sporophytcs. Natural size. C, a capsule of one of 

 the same sporophytes, showing enlarged apophysis, a, below the sporangium, s. 

 Magnified 10 diain. /', capsule uf S/'lackftmn lutetoii, uith umbrella-like apo- 

 physis, (z, below sporauginni, .f Magnified 2 diani. 



study of its structure is left for Part III. It ( onsists at 

 maturity of a yellowish or brown spherical or cylindrical case 

 (fig. 72), which is sessile or raised upon a short or long 

 stalk and contains (a lew or) huncircds or thousands of 

 reproductive cells called spores. The base of this stalk 

 constitutes an organ called the "foot," which is embedded 

 in the gainetophvte ( /, fig. 73). 



68. Nittrition. — The surface of tlie young sporoph\'te, 

 when large and well dexeluped, as it is in the higher li\er- 

 worts and mosses, is green. To a limited extent, therelore, 

 it is able to make food ; but not suffi<ient lor its needs, 



