—2 5 — 



likely that other species may be found to act in the same 

 way. Acording to the writer quoted, the leaves at even- 

 ing squarely face the West, while shortly after sunrise 

 they will be found to face the East. The movement 

 seems to be produced by the petiolules of the individual 

 leaflets, rather than by the petiole of the leaf. The mo- 

 tion which causes the closing of the leaves at night is 

 also located in the petiolules. One striking difference 

 between the night position of marsilia and oxalis leaves 

 is that in the former the leaflets are erect and in the latter 

 the leaflets droop. The explanation for this seems to be 

 a physiological one. In the oxalis the stomata or open- 

 ings through the epidermis are mostly on the under sur- 

 face, and the drooping position of the leaflets protects 

 them through the night. The stomata of marsilia, on the 

 other hand, are mostly on the upper surface, and the 

 leaflets naturally bring their upper surfaces together in 

 the night position. 



Reproduction of Resurrection Fern. — One of the 

 distinguishing marks of the group of Selaginellas to 

 which the resurrection fern (Selaginella lepidophylla) be- 

 longs is the fact that it produces roots from the base of 

 the fronds only. In most Selaginellas the fronds root 

 from any part that happens to come in contact with the 

 soil. But while the resurrection fern remains true to this 

 principle when intact it readily casts it aside when in- 

 jured for if bits of the fronds are broken off and fall in 

 a suitable place, they at once take root as other Selag- 

 inellas normally do, and soon form new plants. The 

 resurrection fern takes its name from its habit of drying 

 up when moisture is scarce and reviving when rains come 

 again. During drouths it becomes very dry and brittle 

 and is then likely to be more or less shattered by the pass- 

 ing of animals or the force of the wind. Whether the 

 pieces thus broken from the fronds later revive and re- 



