28 



FARLOW ON THE GYMNO SPORANGIA 



of an inch long, broadly ovate, acute and closed at the apex, clathrate below ; peridial cells 

 thick-walled, surface papillose, isodiametric, about 38/7, coherent at the apex of peridium, 

 below united in longitudinal rows ; cells about 20m thick by 60u- 80u long, the upper end 

 of each cell projecting inwards and overlapping the base of the cell above ; spores brown- 

 ish, roundish-angular, 25,u to 30a in diameter, cell wall thick, pores well marked. Sper- 

 mogonia numerous in the discolored upper surface of the leaves. 

 On leaves of apple and pear trees. 



Westbrook, Me. (Bolles); Bethlehem, Pa. (Schweinitz) ; North Carolina (Curtis); 

 California (Harkness). Europe. 



The typical R. cancellata is common in Europe and is easily distinguished. It has been 

 published in several series of exsiccati of which I need only mention Libert, No. 394, and 

 Thiimen, Mycoth. Univers., No. 537, where the specimens are very characteristic. The aeci- 

 dia are borne in swollen parts of the under surface of the leaves, but the swellings are by no 

 means so large as those of R. botryapites and they are broad at the base, not constricted as 

 in the last-named species. Although the peridium bears some resemblance to that of R. 

 botryapites and R. transfer mans, it is distinct in having the upper end of the cells pro- 

 longed inwards in the form of a papilla. The periclial cells are quite different from those 

 of R. botryapites but resemble more closely those of R. transformans. R. cancellata 

 must be considered a rare species in the United States as far as at present known. It is 

 only known in doubtful cases in Eastern Massachusetts and it is not enumerated by Peck 

 among the Roesteliae of New York. The fungus mentioned under the name of R. cancel- 

 lata in Bull. Bussey Inst., Vol. n, p. 225, does not seem to me really to be that species. 

 The only specimens which I have examined of the Aecidium cancellation of the Syn. 

 Fung. Car. Sup. and of Caeoma roestelites Syn. Fung. Am. Bor., were in poor condition, 

 and certainly were not typical R. cancellata, and although mentioned in Curtis's list as 

 occurring in North Carolina, there are no specimens in Herb. Curtis to mark the locality. 

 Considering that the species is easily recognized from European specimens, there would 

 probably be no difficulty in recognizing it if it occurred with us. One thing is certain, that 

 the very common Roestelia found on apples in the autumn in Eastern Massachusetts is not 

 R. cancellata. The present species is generally found on the leaves only, but is said also 

 to attack the smaller branches. 



Roestelia cornuta (Ehrh.) Fr. 

 Aecidium cornutum Pers. in Gmel. Syst. Nat. 



Caeoma cylindrites Link, Species Plantarum, Vol. vi, part 2, p. 64, in part ; Schweinitz in 



Syn. Fung. Am. Bor., in part ? 

 Roestelia cornuta Fr., Summa Veget. Scand., Vol. n, p. 510 ; Oersted, Nouvelles Observ., 



PI. iv; Reess, loc. cit., p. 28; Peck, 24th Report; Farlow, Bull. Bussey Inst., Vol. 



ii, p. 225 ; Tuckerman's Plants of Amherst. 

 Ceratitium cornutum Rabenh., Bot. Zeit., 1851, 452. 

 Centridium sp. Chevallier, Desmazieres, et al. 



