Mar., 1913.] Caloplaca Pyracea {AcL) Th. Fr. 99 



The plants of this group excrete a sticky substance by which 

 insects are often captured in large numbers. 



In the Silenes, Tricuspis, Parsonsia, Polanisia and Circaea the 

 secretive and absorbing glands are on the stems, while in Carduus 

 the viscid substance is excreted on the bracts of the involucre. 

 In this case the excretion acts more as a protection to the flower 

 against crawling insects. In certain western species of Carduus 

 the glutinous secretion on the bracts is so abundant that it is 

 impossible for any crawling insects like ants to pass over it to the 

 flowers above. The species in Ohio have the glands on the bracts 

 and insects were observed adhering to them but they are much 

 less prominent. 



CALOPLACA PYRACEA (ACH.) TH. FR., A CRUSTACEOUS 

 LICHEN ON THE SANDSTONE SIDEWALKS OF EAST 



CLEVELAND, OHIO. 



Edo Claassen. 



Owing to the frequent rains last sumnier more algae seemed to 

 grow on the sidewalks than ever before. They were yellowish- 

 green, represented a species of Cystococcus, and occasionally 

 covered the entire surface of the stones. Here and there small 

 specks of a grayish color appeared on them, a fungal growth 

 several mm. in diameter. The mycelitim spread out and continued 

 to do so while its central part began to disappear. In these centers 

 algae again commenced to grow while the mycelium stretched 

 out more and more, surrounding the algae like a ring continually 

 increasing in size. It frequently happened that some mycelium 

 located itself on the central part of this algal layer, thus apparently 

 repeating the former process. It was on these layers of mycelium 

 that apothecia were forming in great numbers. They were yellow 

 to orange-yellow with their rim-like external part, the so-called 

 exciple, lighter in color. When young they were somewhat 

 convex but later on mostly fiat. 



The apothecia contained asci in a more or less mature condi- 

 tion. The spores were very seldom simple, except when quite 

 young and filled with granular protoplasm, but usually even when 

 rather young they were two-celled. Nearly fullgrown spores as 

 well as ripe ones were always two-celled. Although the two- 

 celled spores of this lichen are said to be generally " polar-biloc- 

 ular, " none of this type could be ascertained in the specimens 

 examined. 



All the lichen specimens were concentrically arranged on the 

 stones wherever they had space enough to spread; when full 

 grown their diameter reached 50 to 70 mm. or even more. In the 

 central part of an examined specimen was found an algal layer of 



