56 SEVENTH REPORT. 



globular, somewhat conical-papillate, on a stroma which is erumpent, flattened or almost 

 obsolete, a mere stalk with single perithecia, young ones light red, older ones dark red, 

 none seen collapsed; asci cylindrical while young, clavate when old, 70-90 x 9-18 mw, 8- 

 spored; ascospores sometimes monoseriate, generally biseriate only in the widest part of 

 the ascus, varying from pointed elliptical to oval, the former being long and narrow, the 

 latter thicker and somewhat shorter, 11.5-20 X 4.5-9 mu, the thicker ones usually 14-16 x 

 7-9 mu (this seems to be the mature form), uniseptate, often slightly constricted at 

 middle, especially the thick ones, hyalin in color. 



Habitat, on dead bark around the cankered spots on yellow birch, Betula lutea, Port 

 Sanilac, Michigan. 



The difference in shape and dimensions of spores seems to be due, to some extent at 

 least, to the maturity of the spores and the way in which they lie in the ascus. It seems 

 as if the spores may he pointed elliptical, almost spindle-shaped in the younger stage, while 

 lying closely packed obliquely in the ascus, and later, on becoming free, or on absorbing 

 more reserve food they become thicker, shortening slightly as they swell out laterally and 

 becoming rounded instead of pointed. 



Whether this fungus, Nectria coccinea is the cause of the canker on the yellow birch, the 

 observations of course have not determined, but in view of the fact that other species of 

 Nectria are known to produce canker of many species of trees it would not be very sur- 

 prising if this species also could produce the same reaction on some hosts. Only experi- 

 mental work can determine that point, and it is hoped that some work can be carried out 

 along this line. ]\Ir. Preston has made pure cultures of the Nectria and is at present en- 

 gaged in studying some of its characters under culture. 



Conclusion: The yellow birch is subject to a canker which causes great disfigurement 

 of twigs and large branches, greatly impairing their functions. 



The disease is local, not spreading indefinitely from a given point of infection, but 

 spreads by new inoculation. 

 . The points of infection are often the bases of dead lateral twigs, and the cause of the 

 trouble is probably a wound parasite of some kind. 



The perithecia of Nectria coccinea (Pers.) Fr. were found associated with the cankered 

 spots, both larger and smaller, and possibly this is the cause of the disease. As yet there 

 is no experimental proof of this supposition. 



University of Michigan. 



A SPECIES OF HORMODENDRUM ON ARAUCARIA. 

 Jas. B. Pollock. 



The attention of the writer has been called recently to an olive colored mold-like growth 

 on the surface of living branches and leaves of an Araucaria grown as a house plant by Mrs. 

 R. C. Davis of Ann Arbor. The growth is not copious, l)ut is easily visible to the naked 

 eye by the fact that the parts coated by the fungus are of a noticeably different color from 

 the unattacked parts, the former being a darker olive green or brownish green color. 



A hand lens showed a filamentous mycelium, and on placing some of the infested leaves 

 in a moist chamber for a few days a well developed growth of conidiophores and conidia 

 was found, and from these the fungus was easily identified as a species of Hormodendrum , 

 but did not seena to be exactly like any of the species described by Saccardo in the Syl- 

 loge Fungorum. On looking up the literature it became probable that it was Hormen- 

 dendruni cladosporioides Sacc. A fungus that has been described by several authors as a 

 form of a polymorphic fungus, Cladosporiimi herbarum. 



Later the fungus was found in a green house at Ann Arbor growing on diseased violet 

 leaves, associated with Alternaria violce and at the present time experiments are going on 

 at the University of Michigan to determine whether it is parasitic on the violet, and if 

 possible to discover whether it is a form of Cladosporiuni herbarum. 



Only one of the species of Hormodendrum has been described as an active parasite, H. 

 Hordei, a species quite destructive to barley. If the one found on Araucaria is a parasite 

 it is certainlv not a very active one, since it may be present for a considerable period of time 

 without visibly injuring the host. When the Araucaria was first brought to notice it had 

 been badly injured in certain portions, but no trace of the Hormodendrum was found on 

 the obviously injured part, and the part occupied by the fungus showed no serious results. 

 Another Araucaria in the green house mentioned above was also found to have the same 

 fungus on it, nor did it seem to be doing any damage there. 



