ORGANS OF REPRODUCTION. 187 



which have the whole petiole early exposed to the air, grow 

 much more towards the upper part of the petiole." 



It will be seen that the above results of M. Trecul differ in 

 several important particulars from those of De Merckhn, and 

 that the development of leaves is by no means such a simple 

 and uniform process as was supposed by him. Further investi- 

 gations are however still required before we can be said to have 

 arrived at altogether certain conclusions upon the subject. 



For further observations on this subject the reader may con- 

 sult, De Mercklin Observations sur VHistoire du Developpement 

 des Feuilles. Annales des Sciences Nat. Bot. 3d ser. vi. 215 ; 

 and Trecul, Comptes Rendus for 1853. 



CHAPTER 4. 



ORGANS OF REPRODUCTION. 



Under the head of Organs of Reproduction we include the 

 flower audits appendages ; and they are so called, because they 

 have for their oflSce the reproduction of the plant by the fonna- 

 tion of seed. Plants with conspicuous organs of reproduction 

 are called Phanoyamous, Phanerogamous, or Flowering; while 

 those in which these parts are concealed or obscure, are termed 

 Ciyptogamous or Flowerless. The former division includes 

 Dicotyledonous and Monocotyledonous Plants ; the latter Aco- 

 tyledonous Plants. 



The parts of a flower (as will be particularly sho-mi hereafter) 

 are only leaves in a modified condition adapted for special pur- 

 poses ; and hence a flower in an unexpanded state or a flower- 

 bud is analogous to a leaf-bud, and the flower itself therefore 

 to a branch the internodes of which are but slightly developed, 

 so that all its parts are situated in nearly the same plane. As 

 flower-buds are thus analogous to leaf-buds they are subject to 

 similar laws of arrangement and development. 



Section 1. Inflorescence or Anthotaxis. 



The term inflorescence is applied generally to indicate the 

 floral axis and its ramification, or the arrangement of the flowers 

 upon that axis. Under this head we have to examine — 1st, 

 The Leaf from the axil of AA-hich the flower-bud arises : 2nd, 

 The Stalk upon which the flower is situated ; and 3rd, The 

 Kinds of Inflorescence. 



1. Floral ]^eaves or Bracts. — "We have already stated 



