254 Vegetable Mortars. 



their tips the elliptic spores, exactly in the same manner as in 

 Nidularia and its allied genera, as illustrated by Talasne. 



In Sphcerobolus there is but a single free sporangium, 

 whereas in Nidularia, and its more immediate allies, there are 

 several which are at first immersed in a transparent jelly, and 

 attached to the walls by means of a highly elastic peduncle, 

 sometimes of a complicated structure. These peduncles in 

 wet weather are washed out, so that the sporangia hang 

 over the edge of the cup-like peridium and at length become 

 detached. 



It has even been asserted in a communication made to the 

 French Academy a few months since, that these fungi have 

 the power of darting out their sporangia. The communica- 

 tion, however, does not amount to much, and is simply as 

 follows : — 



"Being, in 1846, at La Poussiniere, a locality in the 

 environs of Nantes, I met with beautiful specimens of Gyathus 

 striatvs on the trunk of a tree which had been prostrate for a 

 long time, serving as a bench ; and I remarked that the nume- 

 rous little lenticular bodies produced by this fungus were 

 suspended by their threads to the leaves of trees more than a 

 metre above the fungi which had produced them. They were 

 all on the lower surface of the leaves, and had evidently been 

 darted out by the Gyathus. ,} 



As there is no mechanism by which this could have been 

 effected, we must regard this account for the present as prob- 

 lematical. Without denying the author's facts, we may, 

 without offence, demur to his explanation of them. 



We now come to the second plant, Pilobolus crystallinus* 

 in which the explosion is effected in a very different way. This 

 little plant is extremely common in autumn on the dung of 

 various animals, especially that of pigs and horses. It has, 

 however, been observed by Ferdinand Cohn, on a decayed 

 mass of some species of Oscillatoria, a genus belonging to the 

 Algaa. It is conspicuous frequently from its bright yellow or 

 orange stem, and deep olive brown or black sporangia, the 

 former of which almost always sparkles with little dew-drops, 

 in which a minute elongated worm or worm-like body has been 

 seen occasionally to move with great rapidity. The nature of 

 this body has not at present been fully determined, and it is 

 not certain that observers have always seen the same thing, 

 for the motion is described by some as taking place in the 

 cavity of the stem, while Durieu de Maisonneuve observed 

 it in a colourless cell produced in place of the sporangium. 

 Some think that it may have some important vital connection 

 with the plant, but this does not seem very probable, and, as 

 * From ir?\os, a_hat, and /8aAAa>, I cast. 



