ENDOPHYLLUM-LIKE RUSTS OF PORTO RICO 
45 
oecious. The discoveries of KunkeF in the case of Caeoma nitens 
(Schw.) Burrill and of Fromme,-^ in connection with Aecidium 
tuberculatum EUis and Kellerm., by means of which they proved 
the tehosporic character of the supposed aecidiospores, also acted 
as a great stimulus in our work. We tried to a limited extent 
the agar medium recommended by Kunkel, but, laboring under 
the rather trying tropical conditions, we came finally to use almost 
exclusively the water surface method. This method proved very 
efficient, as well as very simple and easy to manipulate. All our 
germinations were tested successfully again and again by sowing the 
spores on the surface of water drops placed on slides which were 
supported up from the bottom of moist chambers. Inverted Petri 
dishes, with a little water in the bottom to seal the cover, served 
admirably for the latter. 
In order to secure the best results, the spores must float on the 
surface of the water, so that their germ-tubes may grow up into the 
moist air. If, on the other hand, the spores are completely im- 
mersed, the tubes then appear much like those from true aeciospores. 
We found also that by chopping up bits of the host tissue with the 
sori on them, and putting these so that they were not covered with water 
but merely wet, much better and more abundant germination of the 
telia resulted. 
When once we became convinced of the short-cycled character of 
one of these aecidium-like rusts, we became suspicious of all and deter- 
mined to try out the spore germinations of every aecidioid rust with 
which we came in contact. Our first successful find was in connection 
with Aecidium Wedeliae, one of the commonest and most widely dis- 
tributed of Porto Rican rusts. Professor Arthur states^ that Dr. 
Stevens had made the suggestion that the alternate host in this case 
might be Cyperus, bearing Puccinia canaliculata (Schw.) Lagerh. 
However, the very commonness of the Aecidium, occurring as it does 
in all sorts of situations, all over the Island, on the host Wedelia 
trilobata, combined with the comparative rarity of the Cyperus hosts 
bearing Puccinia canaliculata, made us at once doubtful as to any 
possible connection between the two. As stated above, our suspicions 
were confirmed when trials of the germination of Aecidium Wedeliae 
2 Bull. Torrey Bot. Club 40:361-366. 1913; 43:559-569. 1916. Amer. 
Journ. Botany i: 34-37. 1914. 
^ Bull. Torrey Bot. Club 42: 55-61. 1915. 
' L.c, p. 318. 
