CARTJEL'S ARRANGEMENT. 191 



it cannot be understood by the pupil until after lie has made 

 himself acquainted with the morphology and physiology of Cryp- 

 togams and Phanerogams and the details of the reproductive pro- 

 cess in the several orders. 



Caruel's primary groups are : 



I. PHANEROGAMS. Plants trimorphic, one form neutral, pro- 

 ducing agamically two sexual forms, male and female respectively ; 

 neutral form originating from a fertilized oosphere and developing 

 into a pro-embryo, like the embryo originating longitudinally ; 

 evolution indefinite. Male form represented by the pollen in the 

 anther. Female by the ovule, ultimately the seed : evolution defi- 

 nite, containing the oospheres in a closed oogonium. 



II. SCHISTOGAM^:. Plants trimorphic. Neutral form origina- 

 ting from a fertilized oosphere, developing, like the embryo, trans- 

 versely : evolution indefinite. Male form a vermiform phytozoon 

 (spiral spermatozoid) formed within an antherocyst. Female form 

 an oogemma, then a seminulum, with definite evolution, containing 

 an oosphere in an open oogonium. (Characeae.) 



III. PROTHALLOGAMJE. Plants trimorphic. Neutral form pro- 

 duced from a fertilized oosphere, developing, like the embryo, trans- 

 versely : evolution indefinite. Male form a vermiform phytozoon 

 formed within an antheridium. Female form a spore, developing 

 into a prothallus : evolution definite, containing a naked oosphere 

 within an archegonium. , (Vascular Cryptogams.) 



IV. BRTOGAMJB. Plants trimorphic. Neutral form originating 

 from a fertilized oosphere, developing, like the embryo, longitu- 

 dinally : evolution definite. Male form a vermiform phytozoon 

 from an antheridium. Female form a spore developing into a 

 thallus or " cormus :" evolution indefinite, and containing a naked 

 oosphere in an archegonium. (Muscineae.) 



V. GTMNOGAMS. Plants di-, trimorphic. In the trimorphic 

 form the neutral form is an oospore arising directly from a fertilized 

 oosphere : evolution indefinite. Male form a zoosporiform phyto- 

 zoon from an antheridium. Female form a spore developing into 

 a thallus : evolution indefinite, containing an oosphere in a naked 

 open oogonium. In the dimorphic plants, two sexual forms only, 

 the male a phytozoon or pollinidium. In the monomorphic plants 

 a single form without sexual distinction : evolution definite or in- 

 definite. (Cellular Cryptogams.) 



In the following pages the arrangement adopted is, for Dicoty- 

 ledons mainly that of De Candolle, for Monocotyledons that of 

 Bentham. 



