HETEEOTAXY. 189 



deviations from the customary arrangement of the in- 

 florescence, such as the change from a definite centri- 

 fugal form of inflorescence to an indefinite centripetal 

 one. This occurs occasionally in roses, where the 

 shoot, instead of terminating in a flower-bud, lengthens 

 and bears the flower-bud on its sides as in a raceme. 



In the hyacinth, the inflorescence of which is pro- 

 perly indefinite, the terminal flower may frequently be 

 found to expand first, though in order of development 

 it may have been the last formed. 



It occasionally happens that certain plants will, 

 contrary to their usual custom, bloom twice in the 

 same season ; this usually arises from the premature 

 development of buds which, under ordinary circum- 

 stances, would not unfold till the following spring. 

 In these instances of what the French term " fleuraison 

 anticipee," the position of inflorescence is not changed, 

 but there are other cases where the position of the 

 inflorescence is altered, as in the laburnum, where, 

 in some seasons, racemes may be seen springing from 

 short lateral " spurs " along the sides of the branches, 

 as well as from the extremities of long shoots. 



Of a similar nature are those cases wherein stems 

 or branches usually sterile become fertile ; this happens 

 in EquisetacecB,^ in Restiacece, and other orders. In the 

 equisetums, the condition in question has been specially 

 noticed to occur after prolonged drought. 



Equisetacece are likewise subject to an anomaly called 

 by Duval Jouve interruption of the spike, and wherein 

 the scales bearing the spore cases are separated by 

 whorls of branches instead of forming one compact 

 unbroken spike as usual. 



This alternation of the organs of vegetation and 

 reproduction may also be seen occasionally in Typha, 

 and other plants. 



Kirschleger describes a case in which the male cat- 

 kins of Salix cinerea were placed at the ends of the 



I Duval Jouve, ' Hist. Equisut. France,' 1864, p. 154. 



