316 



HUTCHINSON'S POPULAR BOTANY 



they form the most showy 

 portion of the inflorescence, 

 theflowers themselves being- 

 small and inconspicuous. 

 The names bracteate and 

 ebracteate are applied to 

 flowers according as they 

 possess or do not possess 

 these modified leaves. 



Here is a flower that 

 will be readily recognized 

 (fig. 380). No lover of 

 green lanes and sunny 

 meadows bordering banks 

 can be a stranger to the 

 Cuckoo-pint or Wake 

 Robin (Arum, maculatum), 

 with its " ear-like spindling 

 flowers," as Clare calls 

 them, " betinged with 

 yellowish, white, or purplish 

 hue." But let us be clear as 

 to what we are looking at. 

 The figure does not represent a single flower, but an inflorescence, the numerous 

 flowers of which are congregated round the narrow lower part of the club- 

 like column or spcul.ix, while the sometimes spotted enveloping case is simply 

 a special kind of bract, known as a spathe. Any large spadix-ensheathing 

 bract, indeed, is termed a spathe, and such leaves are quite distinct from the 

 foliage leaves both in form and functions. The spathe of Amorphallus 

 titrmum, an Aroid of Western Sumatra, measures nearly six feet in diameter, 

 while its purple spadix attains a height of nearly six feet, and a single leaf 

 has been known to cover an area of forty-five feet in circumference 

 (fig. 384). 



In a large number of plants the bracts are collected in a whorl around 

 a cluster of flowers, and then we have what is called an involucre. Such 

 an arrangement is often of great service to the densely packed florets, 

 particularly during the night, when loss of heat by radiation is largely 

 prevented by the closing of the involucres. The Yellow Goatsbeard 

 (Tragopogon pratensis) and Dandelion (Taraxcicum officinale) may serve for 

 illustration (fig. 386). Could any more perfect arrangement have been 

 devised for protecting their clustering florets from sudden changes of 

 temperature than these circles of stout little bracts ? The Wood-anemone 

 (A. nemorosa), whose white or delicate crimson petals open in April or May, 

 has a whorl of three leaf-like involucral bracts at some distance below its 



FIG. 383. OAT (Avena saliva), 



With branc.hed inflorescence (panicle). To the ri?ht is a single spikelet 

 ilarsred, showing the parts more clearly. 



detached and 



