62 "WILD FLOWERS OF SPRING. 



acid flavour, so much admired by schoolboys, arises 

 from the presence of binoxalate of potass (oxalic acid), 

 and if taken in large quantities might be injurious. 

 It formed part of the old "green sauce" which in 

 former days always accompanied fish on the table. 

 Villagers yet use the expressed juice to remove spots 

 and ironmoulds from linen, and it forms without ex- 

 ception one of the most pleasant acids for turning 

 milk into whey for a drink in fevers. A yellow species 

 of the wood-sorrel (Oxalis corniculata), is also indi- 

 genous, but is extremely rare. 



Later, in the moist recesses of the wood, we may 

 find the Twayblade (Listera ovata), one of the Orchis 

 tribe. The flowers are small, green, in a tender raceme, 

 and grow about hali'-way down a stalk about a foot 

 high. The two broadly ovate leaves are from two to 

 four inches long. Glance for a moment at the veins 

 in its leaves ; they will be found to run from the top 

 to the bottom, and do not form a network, which is so 

 conspicuous in other plants : this is one of the distil 

 guishing features of the Orchis tribe. The early 

 Purple Orchis (Orchis mascula) shows its tall stem 

 m the woodlands as well as in the meadows ; but the 

 brown Bird's-nest Orchis (Listera nidus-avis) is a 



