Notes on Scleroplea aurantiorum and 

 Mycosphaerella lageniformis 



CHAS. W. METZ 

 POMONA COLLEGE, CLAREMONT, CALIFORNIA 



The two new ascomycetes described in the last number of this Journal by 

 Mr. H. Rehm are species found in Southern California on orange and lemon trees. 

 The first record of these is from orange leaves taken at Corona, California, by Mr. 

 Prizer of Pomona College. Later the writer found them in orchards near 

 Claremont. 



The descriptions of the habit of these fungi, given by Mr. Rehm, are based 

 upon two or three specimens, and are not strictly characteristic. The leaves upon 

 which the fungi are found look almost exactly like leaves affected with withertip, 

 (Colletotrichum gloeosporioides Penz.) (See "Withertip of Citrus Trees," by 

 E. O. Essig, P. C. Journ. Ec. Bot. 1-25). The yellow, shrivelled areas may be 

 at the tip, edges, or in the body of the leaf, but are invariably bordered by a brown 

 or dark yellow margin. The perithecia of the two, especially those of Scleroplea 

 aurantiorum, so resemble the acervuli of the withertip that to the naked eye they 

 are indistinguishable. They never accompany the withertip, however, at least in 

 this vicinity. 



Both the Scleroplea and the Mycosphaerella are often found on the same leaf, 

 but the larger and less congregated perithecia of the former, usually serve to dis- 

 tinguish them. Whether or not they are parasitic is not known. Certainly they are 

 not found on any but living leaves, so far as I am aware. Fallen leaves, and 

 hanging dead leaves, show no signs of their presence; nor do leaves mechanically 

 injured. Likewise weakened leaves on trees attacked by squirrels, or otherwise 

 impoverished, show no signs of attack. On the other hand, the fungi apparently 

 are of no appreciable harm to infected trees, as they occur on very few trees, and 

 do not spread rapidly. The writer has only found them on one or two lemon, and 

 perhaps a dozen orange trees in this vicinity; and only on two of the latter were 

 they abundant. On these two the affected leaves were all on the south side, facing 

 the road, the other parts of the tree being entirely free from infection. From one 

 tree about three hundred leaves were taken in an area of a few square feet. None 

 of the trees surrounding these two showed any signs of the fungi. At Corona Mr. 

 Prizer found one tree on which a large part of the foliage was affected, while at 

 Riverside investigation shows only a few scattering leaves with any signs of it. 

 The tree at Corona is the only one known to me, on which the disease, if such it is, 

 is conspicuous. At any rate the survey has been entirely too inadequate to justify 

 any conclusions as to the economic importance of the fungi, even if they are both 

 parasitic, as Mr. Rehm believes. 



The characters of the fungi themselves can best be seen from the accompany- 

 ing figures (Figure 45) prepared by the writer. These have been drawn to 

 scale, so that an accurate comparison of size and form can be made. The perithecia 



