232 MORPHOLOGY OF ANGIOSPERMS 



As there are no naked flowers, this group does not have as 

 primitive members as do the three preceding ones. The sta- 

 mens are extremely variable in number, ranging from three 

 to indefinitely numerous, showing the primitive spiral charac- 

 ter; while the carpels are usually three and sometimes form a 

 syncarpous pistil. The enormous flow T er-cluster is ensheathed 

 by a great bract (spathe) that is more or less tough and even 

 woody, a feature recalling the same tendency in Pandanales 

 and Helobiales. As the axis of inflorescence is sometimes 

 thickened and the flowers more or less embedded in it, the 

 inflorescence is often spoken of as a branching spadix. 



These characters indicate a group as a whole considerably 

 further advanced than the preceding ones in the constant pres- 

 ence of a definite perianth, although it is undifferentiated. The 

 association of floral envelops with a spathe is of interest, but 

 in such conditions a highly developed perianth could not be 

 expected. While there is doubtless anemophilous pollination, 

 entomophily must exist to a certain extent. The whole struc- 

 ture suggests one that is intermediate between the dominance 

 of bract and perianth, between anemophily and entomophily. 



Palmales, therefore, differ from Glumales in the definite 

 trimerous perianth, as well as in numerous other features; 

 from the Helobiales in that the number of carpels is constant ; 

 biit through Phytelephas and Coryphanthe, with their rudimen- 

 tary perianth, as well as through general habit, the connection 

 with Pandanales seems clear. It seems probable, therefore, 

 that the Palmales have been derived from the Pandanales, sur- 

 passing the Glumales in floral development, but not reaching 

 the differentiation of calyx and corolla and epigyny attained by 

 the higher members of the Helobiales. 



\ 7 . SYNAETHAI/ES.* This includes a small family (Cy- 

 clanthaceae) of the American tropics, represented by about 45 

 species, and usually and naturally associated with the screw- 

 pines and palms. The flowers are in an unbranched spadix, 

 either scattered or in a close spiral, and there is generally an 

 evident bract-like perianth in one or two cycles. The stamens 

 range from six to indefinitely numerous, and the carpels are 

 one to four. In the staminate flowers there is no trace of car- 



* SYNANTHAE of Engler. 



