("9) 



pendages move about as a result of changing conditions of 

 moisture and these mechanical movements assist in scat- 

 tering the spores. A somewhat analogous device is found 

 in connection with the spores of the equisetums or horse- 

 tails, though the appendages in this case are attached to 

 the spores. Near the slide illustrating this feature of the 

 horse-tails is one showing the spores and spore-cases of the 

 common polypody; the spore-case here is provided with 

 a sort of spring, by the action of which the spores are 

 violently ejected, catapult-fashion. Another preparation 

 shows the structure of the stem of the moonwort (Botry- 

 chium) as it appears in a cross section. And yet another 

 shows a cross section of the submerged stem of an aquatic 

 plant with its large air spaces and poorly developed 

 strengthening tissues. On the last table, at the left as 

 one enters the landing, is a preparation showing "pollen- 

 grains" from the flowers of a shrub of the mallow family, 

 the grains being in this case globular and covered with 

 small sharp points. Grains of this sort are carried by bees 

 from the anthers of one flower to the stigma of another, 

 thus resulting in cross-fertilization. The last slide illus- 

 trates the structure of the wood of a young pine stem in 

 cross section and brings out clearly the anatomical basis 

 of the annual growth rings. 



(c) Local Flora. In this collection it is designed to 

 illustrate every plant-species growing naturally or without 

 cultivation within one hundred miles of New York City. 

 For the most part specimens of the plants themselves are 

 used, but in cases where the structure of the plants renders 

 this method undesirable, or impossible, a photograph or 

 a drawing is substituted for the plant-specimen. This 

 collection is displayed in swinging frames which are placed 

 so as to correspond in a general way to the sequence of the 

 cases of the synoptic collection already described; thus, 

 the first stand is near the first museum case as one enters 

 the west hall from the top of the staircase. All of the 

 plant groups are here represented by those members that 



