REVIEW AND CONCLUSION 417 



The AMARANTACE.E, URTICACE^) and many of the 

 EUPHORBIACE^S have but one whorl to the perianth, 

 being without petals, and are for that reason often 

 classed in a third section the MONOCHLAMYDE^E ; but 

 the EUPHORBIACE^E seem in their schizocarpic fruit and 

 the arrangement of the ovule (pendulous with ventral 

 raphe) to be not distantly allied to the GERANIACE^E ; 

 the AMARANTACEyE are from the nature of the fruit 

 and the curved embryo, usually placed near a family 

 (CARYOPHYLLACE.E) of the POLYPETAL.E, which has 

 not here been referred to ; and for similar reasons the 

 CUCURBITACE^E are also considered by some to belong 



to the POLYPETAL.E. 



All the plants belonging to these orders are DICOTY- 

 LEDONS and very different in almost every respect 

 from the AMARYLLIDE^E, LILIACE^E, PALMED, AROI- 

 DE.E, MUSE^E, CANNED, ZINZIBARE^E, MARANTE^ 



ORCHIDE^E, which consist of MONOCOTYLEDONS 

 only. - The gulf between the two classes is indeed a 

 very wide one and not confined to the seed alone. 

 For, as was pointed out in (p. 68) when studying the 

 germination of seeds, monocotyledons are seldom 

 woody and their larger plants do not often branch above 

 ground. Most are perennial herbs with rhizomes or 

 bulbs, and the latter are very rare among dicotyledons. 

 The leaves are as a rule simple, with parallel or basal 

 venation and entire ; or if compound as in the palms, 

 have a totally different appearance. Finally the flowers 

 are usually enclosed, at least in the earlier stages, in a 

 spathe, and their parts are in threes not fours or fives. 



Our study of the relationships of plants has thus 

 led to a progressively larger and larger grouping, until 

 27 



