PINK KNOTWEED 



in late August and September. As a matter of fact, 

 it. is pinker and more flowery when out of blossom than 

 when in, for there is no corolla, and as the calyx en- 

 larges to protect the tiny seed it 

 grows pinker, so that a raceme 

 apparently in the full flush of 

 rosy bloom is really a spike of 

 calyxes mothering the half- 

 ripened fruits. 

 There seems to be very little 



method in the arrangement of 



the opening flowers— it is a sort 



of free for all— they appear along 



the axis of the spike apparently 



as it happens, but eventually all 



arrive, and arriving is the main 



thing. Like all the Polygonums 



its joints are swollen, its upper 



stems more or less glandular, in 



order to discourage the ants, and 



the tiny seeds are full of starch, 



hence sought by the birds. Poly- 

 gonum lapathifdlium blooms at 



the same time as Pennsyhanicum, 



is perhaps a little taller, the 



raceme paler and more drooping, 



the flowers a whitish pink with green shadows, other- 

 wise the two are very similar in habit and appearance. 

 The Common Smartweed, Polygonum persicdria, is 



not native but introduced, and is an abundant weed 



about dwellings and in barnyards. Its pink spikes 

 are shorter and less slender than those of P. Pennsyl- 

 vamcum and most of its leaves have dark triangular 



37 



Pink Knotweed. Polygonum 

 Pennsylvdnicum 



