264 



Minnesota Plant Life. 



appressed to the seed-coat layers. The lower families of the 

 order are devoid of perianth, while in the higher families, such 

 as the pinks, both calyx and corolla are well developed. 



Almost all the families hitherto mentioned — with the ex- 

 ception of the pinks and portiilacas — are characterized by the 

 quite general failure of the flowers to develop two kinds of 

 perianth leaves. When only one layer or whorl of perianth 

 leaves is present in the flower, this group of parts is regarded 

 as the calyx, hence the great majority of plants in the families 

 that have been under examination are considered to be devoid 

 of petals. In the remaining families both calyx and corolla are 



for the most part present, al- 

 though there are numerous 

 exceptions, especially in the 

 lower families of the series. 

 The fifteenth order in- 

 cludes the water-lily family 

 and a curious little related 

 plant known as the horn- 

 wort, also of aquatic habit. 

 Here, too, is placed the well- 

 known crowfoot family, to 

 which the anemones, lark- 

 spurs, peonies, buttercups, 

 aconites, columbines, marsh- 

 marigolds or crocuses, gold- 

 threads, meadow-rues and 

 clematis belong. In this 

 order, also, arc included the barberries and their allies, the moon- 

 seeds, the magnolias, the pawpaws, the laurels and a few small 

 exotic families not rci)resented in the United States. 



Water-shields. The water-lilies in their various forms are 

 familiar iidiabitants of the lakes and ponds for which Minne- 

 sota is so justly famous. There are a number of varieties, 

 some more common than others. One of the most inter- 

 esting is the water-shield, which alone has perfectly shield- 

 shaped leaves that always float upon the surface of the water. 

 The leaves of the iiulian lotus are also trul\ shield-shaped; 

 however, main- of tlieni do not l1oat u])on the to]) of the water, 



Fig. 124. Water-shield. After Hritton and lirowii. 



