i 5 8 DISEASES OF TREES 



thinner endosporium, about 66 microm. long and 17 microm. 

 broad. The aecidium form has been observed as Rcestelia 

 cornuta on Sorbus Aucuparia, S. torminalis, Aronia, and other 

 pomaceous plants. The aecidia are situated on orange yellow 

 or red swollen blotches, which are united in various numbers 

 into round or oblong groups. The peridium, which has the 

 shape of a very long-necked bottle, is yellowish, or yellowish 

 brown, twisted like a horn, up to 8 mm. long, open at the 

 shoulder, serrulated, and either not or only ultimately slightly 

 and irregularly lacerated. 



GYMNOSPORANGIUM CLAVARI^FORME 



Teleutospore-layers on Juniperus communis. They are 

 cylindrical, tongue- shaped or band-like, often bifurcated, 

 twisted, and bent, somewhat cartilaginous in texture, yellow, 

 and up to 12 mm. long. Spores spindle-shaped, contracted at 

 the middle, bright golden brown, 70 120 microm. long, and 

 14 20 microm. thick. The aecidium form, Rcestelia lacerata, 

 is met with on species of Cratcegus, and occurs abundantly 

 in smaller or larger groups on orange yellow swollen blotches 

 though frequently covering large areas, especially on fruit- 

 and is usually accompanied by contortions and other deforma- 

 tions. Peridia, flask-shaped when young, later cylindrical cup- 

 shaped, dirty white, rupturing longitudinally to various depths 

 into numerous erect or somewhat outwardly inclined lobes. 



GYMNOSPORANGIUM SABIN^ (SYN. G. FUSCUM) 



Teleutospore-layers on Juniperus Sabina, J. virginictna, J. 

 phaznicea, J. Oxycedrus, and Pinus halepensis. When fresh they 

 are abruptly conical or cylindrical, often slightly compressed 

 laterally and expanding somewhat towards the top, sometimes 

 pectinate, red brown, 8 10 mm. long. Spores broadly 

 elliptical, either not contracted at the middle or contraction 

 scarcely observable, chestnut brown, 38 50 microm. long, and 

 23 26 microm. thick. Thesecidium form, called Rcestelia cancel- 

 lata, is found on Pyrus communis, P. Michauxii, and P. tomentosa. 

 In shape the secidia are like very short-necked bottles, about 

 2 2j mm. high, and several are situated together on orange 



