62 



BOTANY AND PHARMACOGNOSY. 



Osmunda (Fig. 37), Aspidium (Fig. 227), etc. This group is- 

 chiefly characterized by the underground or prostrate stems, 

 known as rhizomes, the part of the plant that is seen above ground 

 being the leaf. 



Fig. 38. Diffsrent types of Perns and fern allies, i, fertile and sterile leaves of slea- 

 der cliff-brake (Pefco Sid/erj) ; 2 , ebony spleen-wort iAsplenium platytteuron) ; 3, rhizome 

 witti two leaves of the common polypody {Polypodium vulgare); 4, maiden-hair spleen- 

 wort (Asplenium tnchomanes) ; 5, temate grape-fern (.Botrychium ternatum) , showing the 

 tripinnate sterile leaf on the left and the upright sporophyll on the right; 6, walking fern 

 (Camptosorus rhizophyllus) showing a new plant developing from the tip of one of the leaves; 

 7, fertile and young sterile leaves of ostrich fem (JDnodea Struthiopteris). 



