280) REport OF THE BOTANICAL DurarTMENT OF THE 
6. Luffa cylindrica (Dish-cloth Gourd). Hight inoculations 
were made on the vines and five on fruits. No effect resulted 
on the vine but a few immature or sterile fruiting bodies oc- 
cured on a dead vine-sliver. Portions of two gourd fruits 
were decayed and contained mature Diplodina pycnidia with 
spores. 
Though it is desirable to have these inoculations repeated, 
they are an indication that none of these cucurbits are normally 
susceptible.*? The fungus had no evident effect on any but 
Luffa cylindrica, though it was able to vegetate and fruit on 
some dead vine-slivers of other species. 
Development of perithecia on the vines of naturally immune 
cucurbits.—It is unusual to find the natural sequence of spore- — 
forms interrupted or to have one entirely omitted. Spores of 
the perfect and imperfect forms of a fungus generally follow 
each other in some definite order, whether the perfect form be 
an oospore, zygospore, teleutospore or ascospore. But at pres- 
ent, there are some well known exceptions in each of the above 
groups: some producing but one known type of spore. 
There has been some notable work done, on some members 
of the “oosporic group,” in artifically causing either type of 
spore to be produced by means of certain culture media and 
environmenti,** and on species of the “zygosporic group,” by 
showing them to be heterothalic and therefore requiring two 
sexually unlike individuals of a sprcies for the production of 
zy gospores.** | 
*? Some recent infection experiments by Dr. G. M. Reed give a compre- 
hensive grouping of cucurbits and other plantsin regard to their suscepti-’ 
bility to some parasitic fungi. Infection experiments with EHrysiphe 
cichoracearum DC. Bul. 250, Univ. of Wis. (Science Series Vol. 3, No. 8. pp. 
337-416), Madison, Wis. 
33 G. Klebs, Zur Physiologie der Fortpflanzung einiger Pilze, Jahrb. f. Wiss. 
Bot. 33: 513 (1899), and also 35: 80 (1900). G. Klebs, Willktirliche Ent- 
wickelungsdinderungen bei Planzen, Jena 1903. 
* A. F. Blakeslee, Zygospore formation a sexual process. Science N. 5S. 
19: 864-6 (1904) Lancaster, Pa. Sexual reproduction in the Mucorinee. 
Proc. Am, Acad. 40: 205-319 (1904), Boston, Mass. Zygospores and sexual 
starins in the common bread mould, Rhizopus nigricans, Science N. 8S. 24: 
118-122 (1906). 
