BRIEFER ARTICLES 



* 



A NEW SPECIES OF ACHLYA 



SIX FIGURES 



906, while studying the Saprolegniaceae 



form 



developed 



university campus. Achlya /< 



and the new form kept growing in pure cultures for over two months. 

 A careful study was made of its growth and structure and some of the 

 obsen-ations made are given at the end of this paper. The specific descrip- 

 tion is as follows: 



Achlya hypogyna, sp. nov.— Hyphae slender, tapering gradually 



ard 



in vigorous cultures reaching a length of i^^™. Zoosporangia nearly cylin- 

 drical, sparingly produced. Oogonia generally borne on short branches, 

 r^cemosely arranged on the main hj-phae, but occasionally terminating a 

 main h>-pha, and very rarely intercalary; globular or rarely oblong, the 

 walls more or less abundantly producing short, rounded outgrowths; 

 yellow when old. Oospores 1-7 (commonly 3-5), centric, diameter 24-36 /*, 

 averaging 27-28 fi, .\ntheridia cut off from oogonial branches just below 

 the oogonia, very rarely absent. Fertilizing tubes arising from the common 



pogynous 



The absence of antheridial branches and the origin of the fertilizin 



or 



guish 

 Saprolegniaceae 



group in Saprolegnia. In two or three 



oogonium 



fer- 



and applied its end to the surface of the oogonium, and in one case 

 an antheridial branch was of diclinous origin. In all such cases, howi 

 the characteristic sub-oogonial antheridia were also present and no 

 tduing tubes were formed from the supernumerary antheridial branaes. 

 It 15 evident that AcUya hypogyna Is closely related to A. racemosa HUdeb., 

 var. sieUigera Comu.^ The general habit, the structure of the oogonia, 

 and the sub-oogonial antheridia are very much the same in both forms ; 



» Htophkey, James Ellis, The Sapndegmaceae of the United States, vv-ith 

 notes on other species. Trans. Amer. Philos. Soc. 17:63-148. pis. 14-20. 1892- 



Botanical Gazette, toI. 45I [ 194 



