DISEASES OF TREES AND SHRUBS. 75 



Spanish moss {Dendropogon usneoides (L.) Raf.), — This epiphyte 

 forms long pendent festoons and is very commonly distributed. 

 It is most abundant, however, along the watercourses, while the ball 

 moss is more abundant on the higher ground. 



Tar-spot [Rhytisma (rytliros^povmrb B. and C). — Thin, black 

 blotches, usually about 4 mm. in diameter, but sometimes as large 

 as 8 mm., are formed on the upper surface of the leaves of the live 

 oak. (PI. XIII, fig. 3.) 



Specimens collected: On Qiicrcus virginianv Mill. — Austin, 176, 490, 547, 2936. 



OLEASTER. 



Leaf -spot (Cercospora elaeagni Heald and Wolf, 32). — In this dis- 

 ease the leaves of the oleaster {Elaeagnus sp.) show on the upper 

 surface an abundance of circular or subcircular spots 1 to 2 mm. in 

 diameter with a definite brown border and a whitish or brown center. 

 The spots are inconspicuous on the under surface on account of the 

 dense, silvery tomentum. There is generally some yellowing beyond 

 the spot and in many cases a pronounced yellowing of the whole leaf. 



Conidiophores amphigenous, densely fasciculate, dark brown, 40 

 by 3.5 to 4 /x, more abundant on the upper surface; spores clavate, 

 straight or slightly curved, nearly hyaline, 28 to 150 by 2.5 to 4 jw, and 

 one to several septate. (PI. IV, fig. 4.) 



Specimen collected: On imported host (species not known) — Floresville, 2861 

 (type specimen). 



OSAGE ORANGE. 



Blight {Sporodesmium maclurae Thm.). — No definite spots are 

 produced on the foliage of the Osage orange {Toxylon pomiferum 

 Raf.). The under surface acquires a diffuse dirty-brown coloration, 

 not so abundant, however, on the upper surface. Considerable chlo- 

 rosis accompanies this disease, and a subsequent defoliation results. 

 (PI. V, fig. 6.) 



Specimens collected: Austin, 1922; Seguin, 2319. 



Cottony leaf -spot {Ovularia maclurae Ell. and Langl.). — This leaf 

 disease is characterized by the cottony appearance of the lower sur- 

 face of the affected areas. The upper surface of the spots is circular 

 to irregular, rusty brown, and they vary in size from 3 to 10 mm. 



Specimen collected : Gonzales, 2694. 



PECAN. 



Leaf -blight {Septoria caryae Ell. and Ev.). — Some of the trees of 

 the pecan {Hicoria pecan (Marsh.) Britt.) in the vicinity of Austin 

 show a large amount of leaf-blight characterized by the presence of 

 large, irregular, chestnut-brown areas on the under surface of the 



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