DISEASES OF OENAMENTAL PLANTS, 85 



Root-knot (Heterodera radicicola (Greef) Mill.). — Observed in 

 only a single locality. Affected plants were much dwarfed. 

 Specimen collected: Austin, 1921. 



COLUMBINE. 



Leaf anthracnose (Gloeosporium aquilegiae Thm.) . — Large marginal 

 spots, usually irregular in outline, are formed on the leaves of the col- 

 umbine {Aquilegia sp.). These diseased areas are yellowish brown 

 in color with a brown border and often a yellowish zone toward the 

 advancing edge of the affected tissue. The lower surface shows the 

 same colors except that they are more dilute. On the upper surface 

 are numerous little dots, the acervuli. Observed in greenhouses only. 



Specimens collected: Beeville, 1866; Austin, 2864. 



CYCAS. 



Blight {Ascochyta cycadina Scalia). — The leaflets of Cycas revo- 

 luta Thunb. turn yellow at the tips, and as the trouble advances the 

 older diseased portions become brown. The pycnidia, black and more 

 or less scattered, form on the upper surface. Observed in a single 

 locality where it was abundantly present and apparently the cause 

 of considerable injury. 



Specimen collected : Beeville, 1852. 



DAISY. 



Dodder (Cuscuta indecora Choisy). — This was observed on the 

 daisy {Chrysanthemum sp.) in a garden at San Antonio. 



Specimen collected : San Antonio, 1664. 



Leaf -spot (Cercospora chrysanthemi Heald and Wolf, 32). — The 

 diseased areas are raised above and sunken below, and vary in size 

 from 2 to 10 mm. They have very definite elevated borders, are sub- 

 circular or irregular in outline and brown in color, becoming grayish 

 with age. The conidiophores, present on both surfaces, are densely 

 fasciculate, brown, septate, 45 to 75 by 4 /*. The conidia are clavate, 

 40 to 120 by 4 ^, many septate, and dilutedly. colored. (PL III, fig. 4.) 



When the spots are abundant the leaf becomes brown between the 

 diseased areas. 



Specimen collected: San Antonio, 1659 (type specimen). 



Leaf-spot. — On the upper surface of the leaves of elephant's ear 



{Colocasia esculenta (L.) Schott.) the spots are circular in outline, 

 5 to 15 mm. in diameter, with a brown center and a surrounding zone 



226 



