2o6 THE STORY OF PLANT LIFE 



upper ovate, half -das ping, and the flowers in the axils 

 of the bracts. 



62. The Knot-Grass Group. 



British representatives of the Order Polygonaceae 

 include the Knot-Grasses, Docks, and Mountain 

 Sorrel, Buckwheat also being frequently found in 

 this country. Amongst foreign types Rhubarb, 

 universally grown in the kitchen garden, is a well- 

 known species. This is a species of Dock. 



Of this Order there are seven hundred and fifty 

 species and thirty genera. They are found, as a rule, 

 in the North Temperate regions, though they extend 

 from the Tropics up to the Poles. Some are Arctic 

 types growing at high altitudes, as Mountain Sorrel 

 and Alpine Bindweed. 



Resembling in many respects the last group, they 

 differ from the Goosefoots in possessing annular 

 stipules or ochreae. In other respects they also show 

 some affinity with the Amaranthacese. 



Some of the tropical types are climbing plants, 

 tall and woody, or woody shrubs. The majority are 

 herbaceous. The leaves are alternate, simple, entire, 

 or with small teeth. The ochrese, or sheathing 

 membranous stipules, clasp the stem at the base of 

 the leaf, and form a distinctive feature. 



The inflorescence is racemose, partly cymose. 

 The flowers are hermaphrodite, but sometimes 

 unisexual. They are regular, and either cyclic or 

 acyclic. In the cyclic flowers the perianth consists 



