PAPERS ON BOTANY 165 
PHACIDIALES 
TRYBLIDIACEAE 
Triblidium Duf. 
Trybhidium refulum (Spreng.) No. 6737. 
ASPERGILLALES 
ASPERGILLACEAE 
Penicillium Link 
Penicillium digttatum (Fr.) Sace. On grapefruit. Palo 
Seco. 3976, (Stevenson). 
MyRIANGIACEAE 
Myriangium Dur. 
Myriangium duriaei Mont. On white scale. Palo Seco. 
(Stevenson) 3886. 
PERISPORIALES 
ERYSIPHACEAE 
Though diligent search was made for powdery mildews 
with perithecia, none were found in Porto Rico. The conidial 
stage occurred on many hosts and with great frequency. It is 
of course impossible to make satisfactory determination of the 
genera and species of these without perithecia. The following 
Erysiphaceae represent merely collections of Oidium and are 
given with the names of the species to which they may belong, 
i.e., with these species which are known to occur on these 
hosts. 
Microsphaera Levéillé 
Microsphaera euphorbiae (Pk.) B. & C. (?) On Chamae- 
syce brazilienses, Mona Island, 6100, Maricao, 4805, Peniuelas, 
4176; on Chamaesyce hypersicifolia, Mona Island, 6405, Ja- 
jome Alto, 5639; on Hibiscus sabdariffa, Mayaguez, 5775; 
on Manihot, Preston’s Ranch, 6606. 
Microsphaera diffusa D.C. (?) On Meibomia sp. Rosario, 
4801; on Meibomia supina, Utuado, 6867, Jayuya, 6075; on 
Meibomia scorpiurus, Manati, 5301, Guayama, 5332; on Mei- 
bomia adscendens, Utuado, 4420, Crotalaria retusa, Sta. Ana, 
3967, Coamo, 843, 5105. 
On Meibomia tortuosa, Penuelas, 9146, on Meibomia sps. 
Mona Island, 6197. 
Sphaerotheca Léveillé 
Sphaerotheca humuli (D. C.) Burr. (?) On Verbena 
(cult.); on Rosa (cult.), Maricao, 767, 4005: on Cosmos 
