94 DR. E. SPEUCE ON EQUATOBIAL-AMEUICAIN' PALMS 



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as is best seen in Iriartea. In Phoenix some species Lave the 

 embryo almost basal, in others it is midway (in P. farinifcray 

 Eoxb., &c.). In Thrinax, a genus which has (by abortion) a 

 solitary carpel, the ripe seed has the embryo in some species at the 

 geometrical apex, in others at a short distance below it ; and so 

 of many other genera. But in the genera with symmetrical fruits 

 the embryo is pretty constant to one position in all the species. 



§ 14. The Niimher of complete Spathes is of great importance in 



defining the Genera. 



A good generic character seems to be afforded by the number 

 of complete spathes, whether one, two, or many ; but it has not 

 in all cases been correctly ascertained. Two spathes coexist in 

 some genera, where the outer of the two may be overlooked, from 

 its being frailer and deciduous at an earlier stage than the inner 

 or from its remaining concealed within the sheathing base of the 

 petiole, as happens to some Oeonomce^ Bactrides^ Astrocarya^ &c. ; 

 and sometimes both spathes fall away with the first expansion of 

 the spadix, long before the flowers are fully formed, which may 

 cause them to escape observation altogether, as in Leopoldinia. 



§ 15. On the Separation of the Sexes, its importance in the economy 

 oftheplanty and the slight value of generic and specific cha- 

 racters fou7ided upon it. 



Contrary to the example of my predecessors, I have made scarcely 

 any use of the sexual phases of the inflorescence in the characters 

 of either species or genera ; for I have found many so-called dioi- 

 cous inflorescences to be often monoicous, and that all possible 

 phases of a diclinous inflorescence may be exhibited by species of 

 the same genus. To explain how this comes about, we must first 

 remark that, with few aberrations, the ternary type prevails 

 throughout the organization of Palms. Not only are the parts 

 of the flower some multiple of three, but there is a tendency to a 

 tristichous arrangement of the leaves, which is most obvious in 

 the Lepidocarya and other slender-stemmed palms; the spadices, 

 if more than one on a leaf-ring (or axil), are commonly three, sis, 

 or nine, the middle one of each triplet being a female, the two 

 lateral ones male spadices ; and the flowers, following the same 

 law, stand normally three together, often half-immersed in an 

 alveole of the rhachis, the middle flower being a female, and the 

 flower on each side of it a male. 



In many palms there is a tendency of the J flowers to become 



