52 Charles E. Bcsscy 



Phylum XV. ANTHOPHYTA. The Flowering Plants. 



Typically chlorophyll-green plants (a few colorless hystero- 

 phytes), ranging from small or even minute plants to great trees 

 a hundred or more meters in height ; alternation of generations 

 obscured by the extreme reduction of the gametophyte to a con- 

 dition of dependence upon the long-lived, leafy-stemmed sporo- 

 phyte. Spores of two kinds (heterosporous), produced on sporo- 

 phylls which are borne in modified, often much reduced strobili 

 (flowers) ; microsporophylls (stamens) normally with two spor- 

 angia (pollen sacs) ; the microspores being set free (as "pollen") 

 when mature; megasporophylls folded lengthwise (constituting 

 the ''pistil"), enclosing the sporangia (ovules) in, which the 

 megaspores remain and develop the minute gametophyte ; arche- 

 gones very much reduced, including little more than the egg, 

 which is fecundated by the non-motile spermatozoids (male nu- 

 clei), resulting in the formation of an embryo sporophyte; mega- 

 sporangia surrounded by one or two enveloping coats (seed 

 coats) ; mature seed with or without endosperm (gametophyte 

 tissue). 



The Flowering Plants are here held to have sprung from strob- 

 iliferous ancestors probably of the type of the Bcnncttitaccac, and 

 as a consequence those Anthophyta are considered to be prim- 

 itive in which the sporophylls are many and distinct. Symphylly 

 and syncarpy are later structural conditions than apophyliy and 

 apocarpy. So also, fewer sporophylls in the anthostrobilus is a 

 later condition derived from the earlier polyphyllous structure. 

 The symphysis of sporophylls is a mode of evolution, and so is 

 their aphanisis. 



Class 33. MONOCOTYLEDONEAE. Leaves of young spor- 

 ophore alternate; leaves of mature sporophore usually parallel- 

 veined ; fibro-vascular bundles of the stem scattered, usually not 

 arranged in rings. 



Order Alismales. Pistils separate, superior to all other parts 

 of the flower. 



Family I. Alismataceae. Aquatic or paludose herbs with 

 mostly radical, often large leaves; flowers small to large; peri- 



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