COHESION AND SUPtelilSSION. 243 



whose older members, as Papaver, are clearly closely 

 allied to, and derived recently from, the Polycarpic* (as 

 Celakovsky points out), and have their parts in threes. 



The corolla of Portulacacese is also 2 + 3-merous, 

 its perianth having three whorls in all, like that of the 

 Papaveracese and Cruciferse. 



In the lily-flower there were five stamens which did 

 not alternate exactly with the perianth-leaves ; the 

 pentamery here was probably due to fusion of two 

 stamens ; but this was not particulary noted. Of the 

 normal three carpels two were partly fused together. 

 The formula of this flower was therefore K2-|- C2|- A 

 2 4- 3 (or 3 -h 2) Gr2 ( — 3). A second terminal flower 

 had just the same structure. A third had a perianth of 

 four leaves, of which one was completely external and 

 one completely internal, and two (lateral) ones which 

 were half external and half internal, representing a 

 fusion of two sepals each with a petal ; there were 

 five stamens and three carpels. The floral formula in 

 this case would be Kl|| Cl|-|- A3 + 2 G3. A fourth 

 flower had the same 5-merous perianth, but androecium 

 and gynceceum were normal. Pentamerous flowers of 

 Pancratium and Narcissus Pseudo-narcissus may also 

 be mentioned.* 



Tetramerous flowers replacing the normal 5-merous 

 ones are not infrequent in Dicotyledons, as in examples 

 observed in Pentas, Primula, and Passiflora ; in this last 

 flower there were only two carpels. 



Trimerous flowers were also exhibited by a Ventas. 

 Fuchsia offers another case. Magnin describes a plant 

 of herb-Paris [Paris qnadrifolia) which was 3-merous 

 throughout, thus showing a reduction hj one member 

 in all its whorls. 



Dimerous flowers, which at the same time naturally 

 become pre-eminently peloric, are common in orchids ; 



* A 5-merous flower of Tulipa persica was recently seen in which two 

 perianth-leaves were completely external, two completely internal, while 

 one was half in- and half outside. There were five stamens alternating with 

 the perianth-leaves, and two carpels. 



