ADDENDA 285 



sculptured epfspore of the spores of reticularias, tubiferas, etc., sug- 

 gest the same thing and more recently we find it in Dianema and in 

 the Stemoniteae; even Stemonitis arrives with clustered spores in 

 groups of four, and we are in sight of a generalization wide. 



It is interesting to note that something of this sort was observed by 

 at least one student long ago. Schumacher, Enurn. PL Sell. 2, p. 

 215, describes Arcyria atra with the characters of an enerthenema, and 

 says "the capillitial threads are some of them diffuse and bear 

 spermatic globules" ! Did he anticipate E. berkleyanum ? See the 

 text under that species at p. 190, supra. 



f. In a paper read December, 1920, before the Mycological Divi- 

 sion of Section G., A. A. A. S., the present writer discussed briefly 

 the physical principles involved in some of the more striking peculi- 

 arities of the slime-moulds. 



It is argued in that paper that the shaping of stipitate sporangia 

 which is so surprising as relating to the ordinary behaviour of fluid 

 masses, as usually observed, is, in part at least, referable to certain 

 well known properties of fluids generally. For this discussion those 

 interested are referred to the article itself in the November number 

 of Mycologia (N. Y.). 



Sufficient to say here that it is a fact, in many cases, that in stipi- 

 tate fructification, so far as observed, the stipe is first to take form, 

 and, as viewed by the writer, in many cases, as it rises, becomes more 

 and more a most delicate but definite ectosarcate capillary tubule, by 

 which ascends the spore-plasm of the point concerned, to such level 

 as may meet the immediate conditions of pressure, of whatsoever 

 source. 



It will be interesting in this view to note the resultant shapes as 

 presented in the sporangia of various genera. One may examine for 

 illustrations Figs. 1, 3, 4, 7, PI. XX., with the thought in mind that 

 the stipe in each case may have served as a capillary tubule to carry 

 up the spore-plasm to the position in which the spores at length are 

 found. In some species of Hemitrichia, for instance, there are spores 

 or spore-like cells found at maturity in the hollow stipe. In other 

 cases the stipe contains refuse matter. 



