EXPLANATION OF PLATE 2. XV 



Class 16. A Flower of the Althae'a officina'lis, Marsh- 

 Mallow July, September. 



17. Genis'ta tincto'ria, Dyer's Green- 

 weed June, August. 



18.. Hyper 'icum pul'chrum, upright 



St. John's Wort July. 



19. Son'chus caeru'leus, blue Sow- 

 Thistle. July, August 



20. Or'chis mas'cula, early purple Or- 

 chis. April, May. 



21. A Spike of Flowers of the Ca'rex pulica'ris, 



Flea Sedge, with two flowers magnified ; 

 one having stamens only, the other only 

 a pistil. June, July. 



22. Two Catkins, from different Plants, of the 



Sa'lix argen'tea, silky Sand- Willow; one 

 bearing flowers with stamens, the other 

 with pistils; with a single flower of each 

 kind magnified May. 



23. A spike of flowers of the At'riplex pat'ula, 



spreading Orache ; with two flowers of 

 different kinds, magnified. June, Sep- 

 tember. 



In this genus, which is the only native 

 one of the class Polygamia, none of the 

 flowers have stamens only. 



24. A small specimen of a Fern, Asple'nium 



trichoma'nes, common Maiden-hair ; 

 and of a Moss, Hyp'num taxifolium. 

 Yew-leaved Feather Moss, both of the 

 natural size October, and through the 

 winter months. 



