HEMISPHAERIALES 



303 



The mycelium penetrates for short stretches, and hyphal columns emerge 

 on the lower sides of the leaves in numerous places where each develops 

 to a small flat fructification. Thus these small fructifications are close 

 together and often form groups up to 7 mm. cross section (Fig. 200, 1). 

 At times they are so close that they look like a single crust; the oldest lie 

 in the center, the youngest at the periphery. At maturity, the single 

 fructifications are circular, 0.5 mm. in diameter and divided in the middle 

 by a hemispherical knob with radial furrows (Fig. 200, 2). In contrast to 

 Hysterostomella, only one central column is present in each fructification 

 (Fig. 200, 3), while in Hysterostomella as many as half a dozen are to be 





Fig. 201. — Asterinella Puiggarii. 1. Section of recently opened fructification. 2. 

 Part of mycelium, showing young and mature fructifications. (1 X 250; 2 X 34; aftir 

 Arnaud, 1918.) 



seen. As a substitute for this, the stromata of Cycloschizon put out from 

 time to time peculiar sinkers which penetrate the interior of the leaf 

 through stomata, serving to anchor and to nourish the stromata (Fig. 

 200, 3 right). In contrast to Hysterostomella, only one loculus, instead of 

 several, is present in the fructification. While in Fig. 199 one must 

 imagine, to right and left, cross and longitudinal loculi, for Cycloschizon 

 all portions of the loculus are visible in Fig. 200, 3. These belong to a 

 single loculus which circumscribes the hyphal knob under the radially 

 striate cover, like a horseshoe or a ring. Hence at maturity the cover 

 does not rupture radially, as in Hysterostomella, but perpendicular to the 

 furrows of the cover with the sterile knob as the center; only subsequently 

 may this circular split fray out by short radial slits. 



Microthyriaceae. — This family shows the purest type of asterinoid 

 habit. It has given rise to the idea of asterinoid life forms (Theissen, 



