502 SUMMA-RY OF CURRENT RESEARCHES RELATINO TO 



Their number varies, the one most commonly observed being seven 

 on a basidium. Before the bursting of the peridinra, the gleba also 

 contains crystals of calcium oxalate. In addition to the spores there 

 are also found in it bodies of a different character, of a spherical, 

 elliptical, or pear-shaped form, and considerably larger than the spores. 

 They are probably functionless basidia, analogous to the cystidia of the 

 Hymenomycetes. There is still again another kind of body found in 

 the gleba, presenting an external resemblance to germinating basidio- 

 spores ; these are of the natui-e of gemmae, simply detached portions 

 of ordinary hypha>, which have ali-cady begun to germinate while 

 inside the sporangium, and complete this process readily after their 

 escape ; while the basidiospores germinate only with great difficulty. 

 The sporangium itself germinates as a whole, playing the part of a 

 single spore with a large number of germinating hypha); but the 

 germinating bodies are chiefly the " gcmmse," possibly at the expense 

 of the spores. 



With regard to the structure of Mitremyces, it shows the greatest 

 analogy to that of Geaster, especially of G. hygromctricus, in the deve- 

 lopment of the gleba. There is, as in that species, no well-marked 

 division of the gleba into chambers ; hyphse proceed from the trama 

 which end in basidia, and more or less completely fill iip the chambers ; 

 but the trama is much more rudimentary. The mode of formation 

 of the spores also presents a great similarity. The collenchymatous 

 layer of the peridium of Geaster hjgrometricus is represented in 

 Mitremyces by a cartilaginous layer. The fructification of Mitremyces 

 is distinctly differentiated into three parts : the gleba, surrounded by 

 the inner peridium ; the cartilaginous layer and its prolongation, 

 which forms the " foot " of the fructification ; and the mycelial 

 envelope, which in the young state envelopes the whole. Between 

 these three pai'ts are separating layers. Growth takes place chiefly 

 in the second, resulting in the destruction of the outer envelope, and 

 in many cases the elevation of the inner peridium. 



Development of Doassansia.* — According to Herr C. Fisch, the 

 only genera of Ustilaginese with a true fructification (in De Bary's 

 sense) are Tuhurcinia, Doassansia, Spliacelotlieca, and doubtfully 

 Graphiola. Of these the two first genera are distinguished by their 

 masses of spores formed free in the tissue of the host. The genus 

 Doassansia was established by Cornu from D. Farloicii, found by 

 Farlow on North American Potamogetons. Fisch now describes at 

 length the development of D. SagittaricB (Protomyces Sagittarice Fck. 

 in Eabenhorst's Fungi europsei) parasitic on Sagittaria sagittcefolia 

 and on the American S. heterophylla. 



This parasite forms circular or less often elliptical or irregular 

 spots on the leaves of the host, at first light yellow, afterwards brown, 

 and from 1 to 2 cm. in diameter, the mycelium filling uji all the 

 intercellular spaces. The fructifications are formed only in the 

 spaces beneath the stomata, and at the time of their maturity the 

 mycelium has entirely disappeared in mucilage. The fructification 



♦ Ber, Deutsch. Bot. Gesell., ii. (1884) pp. 405-10 (1 iil.). 



