ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 493 



conidia of which germinated freely in sea-water ; Fusidium mariUmum, 

 saprophytic on Laminaria and Pelvetia, both on fronds collected above 

 high-tide mark, and on decaying thalli periodically snbmerged ; Mono- 

 sporimn maritimum, also fonnd on decaying Laminaria fronds ; Sporo- 

 trichwn maritimum, on the same habitat ; Gercospora salina, on various 

 sea-weeds in widely distant localities ; ilacrosporium laminarianum, 

 Altsrnaria maritima, and Epidochium maritimum, all saprophytic on 

 Laminaria fronds. The fungi were collected from the Orkneys, Ayrshire, 

 and Dorset coasts. 



Peridermium Harknessii and Cronartium quercinum.* — E. P. 

 Meinecke has instituted a research to determine the relation between 

 Feridermium Harknessii and F. cerebrum, and with the alternate form 

 Cronartium, quercinum. 



Both the above species of Feridermium form galls on pine-trees, and 

 though the identity of the two has yet to be proved by inoculation, there 

 is strong probabihty that they are the same. It is very common on 

 Finns attenuata and several other species, and can be transmitted from 

 pine to pine by infection with fecidiospores, pi'obably through the agency 

 of insects. 



Cronartium quercinum overwinters' on Quercus aquifolia ; new uredo- 

 spores form in spring around the old dead sori and these infect the new 

 leaves, Heteroecism in both the above fungi is facultative. 



Thelephoracese of North America.f — E. A. Burt discusses the 

 genera Exobasidium, TremeUodendron, Eichleriella and Sebacina. The 

 three latter genera possess cruciately divided basidia. 



The species Exobasidium Vaccinii is a parasite on the leaves, etc., of 

 various genera and species of Ericacege ; it is common and of wide 

 distribution ; the leaves show a red spot on the upper surface over 

 against the white fructification beneath. Several other species are 

 described. The species of TremeUodendron are indigenous to North 

 America. The fructifications have the general habit of branched or 

 simple Clavarias and spring up on the ground in deep woods during wet 

 weather in summer and autumn ; seven species are described. 



Eichleriella is described as a Steremn or Cyphella with a tremellaceous 

 hymenium. Sebacina, which occurs as incrustations, is represented in 

 North x\merica by fourteen species. 



Rhizoctonia crocorum and R. Solani.^ — B. M. Duggar has given 

 an historical account of the occurrence of these two destructive parasites. 

 He has examined both species and concludes that Rhizoctonia on crocus, 

 alfalfa and other hosts may be included in one morphological species ; 

 there is no perfect stage of the fungus to give a decision as to its 

 affinity. There seem to be distinct forms or races within the species. 



B. Solani grows on many dicotyledonous plants, and is known so 



* Phytopathology, vi. (1916) pp. 225-40 (2 figs.). 



t Ann. Miss. Bot. Gard., ii. (1916) pp. 627-58 (1 pi.). ; and pp. 731-66 (12 figs, 

 and 2 pis.). 



X Ann. Miss. Bot. Gard., ii. (1916) pp. 403-58 (9 figs.). 



