948 LIFE : OUTLINES OF GENERAL BIOLOGY 



sides as to come to be at the bottom of the hollow thus produced. 

 One may readily visualise such growth processes: (i) By putting 

 one's elbows together on the table and joining hands vertically 

 above it, thus roughly suggesting an ordinary shoot, with united 

 finger-tips as growing point; and next (2) gently raising the hands 

 and arms, but the elbows faster, so that these overtake the slower- 

 rising finger-tips. We have thus a level, which (3) when the elbows 

 are lifted farther and faster, becomes a concave depression, with 

 the finger-tips below wrists and arms, and thus seeming pushed 

 down to bottom, though really but of slower rise. We find less 

 extreme forms of the like predominance of axial growth outrunning 

 the cell-dividing and reproductive apex in many cases; thus Dors- 

 tenia, a herb of the fig order, has its inflorescence practically flat, 

 or only at edges beginning its overgrowth. The broad though still 

 convex apex of the crowded inflorescence which we popularly caU 

 a composite "flower" has arisen in the like way also, only not gone 

 so far. So the long raceme of inflorescence of the probably ancestral 

 bell-flowers (Campanulacese) seems thus to have been arrested by 

 more precocious and less developed florets into the composite 

 flower-head. It is here interesting to note how composite weeds have 

 often small and insignificant flower-heads, like Groundsel {Senecio 

 vulgaris) for commonest of weed type; yet its sister species (S. 

 cineraria, with its buds so closety like heads of groundsel) flowers 

 to exuberant beauty, yet needing gardening care and culture, and 

 warmth also, to attain its perfection. 



But returning to the form of flowers, the simpler orders, like the 

 buttercup family (Ranunculaceae) show the floral whorls (in this 

 case reaUy of surviving primitive spiral leaf-arrangement) in regular 

 and normal descending order, with stamens distinctly below carpels 

 (hypogynous) and petals and sepals in like order again. But in the 

 Rose, see how the lower portion of the axis has outgrown its apex, 

 so that the carpels are inside its almost fig-like cup, and the stamens, 

 carpels, and sepals are uplifted (epigynous) in their due order, yet 

 practically level around its upgrown margin. For intermediate form, 

 see the strawberry flower with its parts on level (perigynous). On 

 this principle, of reproductive checking of growth, it is thus not 

 surprising that in utterly distinct cryptogamic tribes we find the 

 like upgrowing and overgrowing: witness the saucer-like spore-case- 

 bearing surface of Peziza, or its analogues in many lichens, to the 

 completely enclosed "fructifications" of the Gasteromycetes. The 

 principles of flower-making, as we may call them, are thus more 

 general and physiologically intelligible than they have generally so 

 far seemed. 



No popularisation of botany has been more successful, since 

 Darwin's rehabilitation and extension of Sprengel's discoveries, 

 than that of the inter-relations of flowers and insects; and also of 



