February, 1906.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



345 



case of the Begonia. The florist has hitherto been com- 

 pletely vanquished in his attempts to produce a variety 

 of Begonia which shall throw nothing but double 

 flowers on each spray — a single flower alw ays putting 

 in an appearance. Occasionally a blossom is to be 

 found in a curious midway state between the single and 

 double condition, and when this is the case an interest- 

 ing side light as to the connection between stamens and 

 petals is to be seen. It is possible to trace the gradual 

 degeneration of the stamens into the petals; some of 

 these eccentric organs are just simply flattened stamens, 

 resembling miniature petals except for the fact that 

 they are covered with a deposit of pollen. Others have 

 got away from the pollen altogether, ha\c developed 

 the coloured tissue, and are perfect petals in their way 

 except that they are very small. 



Probably one of the most marvellous object lessons 

 in the whole of the plant world bearing on the origin of 

 the stamens is to be seen in the case of the flowers of 

 the Water Lily (Nymphcea alba). By a careful dis- 

 section of the flower of this plant a most instructive 



bring forward further proof in support of the assertion 

 that there is a very intimate connection between the 

 stamens and the petals of the flower. As has been 

 clearly shown on a previous occasion, the petals of the 



ngle Cherry bloom (left) compared 

 ke carpel of double Cherry flower. 



bloom have been obviously developed from the stamens, 



and these latter bring us back to the all-important leaf. 



To trace in a clear fashion the leaf origin of the pistil 



is not quite such a simple matter as it was in the case 



lU • 



elation^ betv 



of the Water Lil 



series of organs may be compiled, in w hich all the stages 

 l>etvveen the stamens and petals may be discerned. 

 Starting away from the outride of the flower with the 

 green sepal, it is interesting to note that this is partially 

 coloured white, offering yet another proof of the origin 

 of the petal. Passing over several rows of perfectly 

 formed petals, it is noticeable that these are steadily de- 

 creasing in size the nearer one gets to the centre. 

 Gradually these petals become modified in form until 

 they are quite narrow, and at last one is seen to be 

 curiously thickened at the point. This point is yellow 

 in coJour, and a microscopic examination of the sub- 

 stance re\cals the fact that it is pollen. 'I"he termina- 

 tion of this organ, which one can call neither stamen 

 nor petal, as one advances inwards, continues to be 

 more and more modified until it rcsohes itself into two 

 thickened parts; eventually these meet together and 

 form the two lobes of the anther. Moreover, at this 

 stage the petal-like process disappears altogether, 

 narrowing down until it forms the filament of the 

 stamen. In the inside rows of the stamens it is not 

 possible to discern any resemblance between the petal 

 and the male rcproducti\o organs. 



A similar process to tli.it which is so striking in the 

 crLse of the Water Lily flower is to be .seen in the 

 blossom of the Pa-ony, and, as well, other instances 

 might be noticed. But it will scarcely be necessary to 



of the other three organs of the bloom which have 

 already been dealt with. As is well known, the pistil is 



A Double Cherry bluum \\iX\\ the 

 exposing the .<mall leaf 



L-ntre petal-i remoNCd. 

 1 the centre. 



composed of one or a number of carpels, and these last 

 b.'ar at the base the wonderful ovules. \ small amount 



