ON CERTAIN EPIGYNOUS MONOCOTYLEDONS. 161 



mens, partly without anthers, arranged 6 and 6 round a 

 pistil. The middle labellum interposed with a fold between 

 the two circles of stamens, the rest of the perigonial organs 

 forming a circle. This twin flower is also common among the 

 female flowers. 



It is seen that the commonest malformations are those in 

 which there are transitions from one condition into another, or 

 multiplications and confluences. Those, however, are more 

 important in which a dimerous or tetramerous flower is substi- 

 tuted for a trimerous. In these, if they have petals at all, the 

 labellum vanishes, and a stamen stands in front of each of those 

 remaining. The flower with eight petals appears to me, like the 

 twin-flower No. 7 B, a malformation originating through the 

 disappearance of the organs standing at the sides where the two 

 flowers are in contact. The labella standing side by side seem 

 to speak in favour of this. The first of these two tetramerous 

 flowers shows,, on the contrary, that the petal next the bract is 

 that which persists. The malformation A. 4. must be ex- 

 plained by a lateral doubling of the individual parts of the 

 flower, and then the middle labellum must be regarded as an 

 altered stamen. 



Cannaceae. Calathea lutea, Spr. The flowers, as the accom- 

 panying diagram shows (PI. V. figs. 3, 4), are enclosed in pairs 

 in two bracts, of which the one standing on the side of the axis 

 represents the primordial leaf (vorblatt)* of a shoot; these 

 bracts, with their flowers, are again enclosed with two other 

 flowers in two older bracts, and the entire partial inflorescence 

 in a large dry involucral leaf (deck-blatt). Each individual 

 flower possesses a small involucral leaf (deck-blatt} standing at 

 its side, as looked at from the axis or from the side where the 

 general involucral bract occurs. This arrangement of the flowers 

 has the greatest analogy to that of the branches, except that in 

 the latter only one branch occurs between a leaf and a primor- 

 dial leaf (vorblatt) 9 instead of two flowers. The unfolding of the 



* The term "primordial leaf" (Bravais) or "vorblatt" (Schimper) is ap- 

 plied to the first leaf or pair of leaves of a shoot, which exhibit peculiarities ; in 

 many cases, they are regarded as representing on the shoot, the cotyledonary 

 leaves of the primary stem. 



SCIEN. MEN. Nat. Hist. VOL. I. PART II. 11 



