POLY TOR ALES 



431 



according to the end forms of the different series toward which they 

 develop. In this sense, the following ten families, whose characters will 

 be given in the course of the discussion are different. Their probable 

 relationships are given in the scheme on page 430. 



Tulasnellaceae. — Perhaps in Tulasnella we have an example of the 

 transition from the endogenous spore formation of typical Ascomycetes 

 to the exogenous formation in the Basidiomycetes. The family presents a 

 series with gradual adaptation to parasitism, accompanied by the develop- 

 ment of the zeugite to a special storage organ. This development is 

 analogous to that we shall find in the Auriculariales and Uredinales. 

 The highest stage attained seems to be that reached by Cystobasidium. 



Tulasnella iPrototremella, Pachysterigma, Muciporus) is mostly 

 saprophytic on bark or dead wood, occasionally parasitic on leaves 



£ Q 



Fig. 273. — Tulasnella deliqucscens. 1, 2. Basidia with basidiospores. 3, 4. Basidia 

 developing uninucleate conidia (X 355; after Juel, 1897.) Tulasnella helicospora. 5, 6. 

 Young basidia. 7. Basidium with basidiospores. 8, 9. Development of basidiospores to 

 conidia. 10. Development of conidium to secondary conidium. (After Raunkiaer, 1917.) 



{e.g., T. grisea on Eichhornia speciosa in Java and T. anceps on Pteris 

 aquilina in Europe). On the substrate they form a bloom which may 

 thicken to a smooth corticiaceous crust. In T. deliquescens its consistency 

 is slimy; in others, as T. thelephorea, the gelatinization of the hyphae is 

 not marked and the consistency is waxy. T. cystidiophora, T. hyalina 

 and T. traumatica have gloeocystidia in their hymenia and are often 

 segregated as Gloeotulasnella. In about half the species the spores are 

 nearly spherical while in the other half the spores are long fusiform, and 

 sometimes curved. The hyphae are binucleate and much branched; 

 in T. deliquescens, there are no clamps and the basidia, which are terminal 

 on the ultimate branches, are irregularly placed and imbedded in the gel, 

 while in T. thelephorea, clamps are abundant, the basidia are more fascic- 

 ulately arranged and form a simple layer on the young crust which does 

 not show the regular parallel structure of a typical hymenium. 



The basidium is pyriform and is cut off by a septum (Fig. 274, 3). 

 The nucleus goes through two stages of division. At the tip, seldom 



