THE CYTOLOGICAL STRUCTURE OF BOTRYORHIZA 



HIPPOCRATEAE 



EDGAR W. OLIVE 



Brooklyn Botanic Garden 



This species of rust, occurring on the host Hippocratea voliihilis 

 L., was first described by the author, in collaboration with Professor 

 H. H. Whetzel, from material collected in Porto Rico in 1916/ It is 

 there recorded as a somewhat peculiar form, though somewhat like a 

 lepto-Uromyces, with only one spore form in its life-cycle. The fol- 

 lowing diagnosis is there published:^ "O. Pycnia wanting (probably 

 not formed). III. Telia mostly hypophyllous but sometimes amphi- 

 genous or caulicolous, generally from a localized mycelium, sometimes 

 from a systemic invasion affecting entire young shoots; localized sori 

 densely crowded in more or less orbicular or irregularly shaped, 

 somewhat hypertrophied pulvinate areas, i mm.-i cm. or more 

 across, the affected areas yellowish when young, when older becoming 

 whitish due to the germination of the spores; in older leaves often 

 killing affected spots, which turn brown, the resultant rounded, 

 swollen dead areas then bearing a striking resemblance to certain 

 insect galls. 



"Telia pulverulent, erumpent, from a definite, superficial, ure- 

 dinoid hymenium which arises just under the epidermis, without 

 peridium ; teliospores uninucleate, borne singly at the end of pedicels 

 which arise from a binucleate mycelium 13-14 by 18-24 n, thin-walled, 

 oval, with a rounded apical protuberance, germinating apically at 

 maturity to produce each a long, cross-septate basidium (promy- 

 celium) bearing 4 basidiospores (sporidia), similar in shape to the 

 teliospores and 8 by 11-12 n. 



"Vegetative mycelium composed of coarse intercellular hyphae, 

 made up of binucleated cells, some of which send large botryose, or 

 irregularly shaped, haustoria into adjacent cells." 



The generic name, Botryorhiza, is, in fact, derived from the botryose 

 character of the haustoria, a striking feature which, so far as I am 

 aware, is possessed rarely if at all by other rusts. It is, however, 



' Endophyllum-like rusts of Porto Rico. Amer. Journ. Botany. 4: 44-52. pis. 



1-3- 1917- 



2 L. c, p. 47. 



337 



