THE MAKING AND ' UNMAKING OF FLOWERS. 



127 



of the sepals, showing that 'thie 'intermediate \v'horl is wanting to sustain 

 the law of alternation of the several parts of the different whorls. Thus, 

 in the male flower of the Stinging Nettle (fig.' 59) the four stamens stand 

 immediately in front of the sepal^^. - 



Extreme degradation is seen in- the Spurges . (fig. 60). Within a cup- 

 shaped involucre are many maile flowers and one female flower but these 

 are reduced to the minimum of simplicity; for a male flow^er consists of a 

 single stamen only ; and the female, of a pistil composed of three carpels. 



We appear to have an ancestral form in 'one or more genera of 

 Australia. In Monotaxis, for exainple, there is a central female flower 

 with an involucre of several bracts, surrounded by sfeveral male flowers. 

 These consist of a calyx, corolla and stamens. Now if all these w^ere 

 suppressed, excepting a single stamen to' ' stand for the male flower, we 

 should have a structure very similar to that of Spurges. 



We must now regard degenerate flowers from the point of view of 

 function. 



If we compare the blossom of a Wallflower with one of a Shepherd's 



4 0 f ^ 



a b c ' d 



Fig. 61.— Clelstoganious buds of Violet. 

 a,' bud' , enveloped in the calyx ; 

 6, calyx removed, showing tlie pistil 

 with .the' five anthers pressed down 

 . npon the summit ; c, a stamen, show- 

 , iqg the large -oval connective with 

 two small anther-cells near the base ; 

 J d, pistil with a short style and trun- 



FiG. 60. — Inflorescence of Spurge.' cated stigma.. 



Purse, one notices that all the features of the former are in adaptation to 

 fertilisation by insects. Thus the sepals form a rigid tube, the receptacle 

 carries two honey-glands at the base of the two passages, down which a 

 bee's proboscis must passi The stigmas are spread out so that they form 

 an angle across which the pToboscis glides, and so removes any pollen 

 brought from a pre\dous flower.' It has a large bright corolla and is 

 strongly scented. " ' : ' , . ■ • 



In the Shepherd's. Pur^e,,a.-mamber '.of the same family, or Crucifers, 

 the flower is very minute and not at all attractive, and there is no scent. 

 The stigmas are massed into a globe, and th'e anthers 'pi-eSs round upon it, 

 discharging their pollen at once upon the stigmatic papilhe. 



The flower has degraded from some condition 'of ancestral conspicuous- 

 ness, because it has retained' its corolla in 'a more or less rudimentary form, 

 but has changed from insect-, to self -fertilisation. 



Violets retreat a step further back\Mirds. After the usual flowers are 

 over, numerous buds appear on the runners under the foliage. These 

 never open, but are perfectly eft'ective for seed-making (fig. 61). 



There is an enveloping .calyx a, no corolla, or only rudiments of 



