THE RUSTS OF NOvA SCOTIA. ERASER. 345 



Family 2. MEI/AMPiORACEAE. 



Basidia external, i. e. germination with a typical pro- 

 mycelium with small spherical sporidia. Telia in more or less 

 definite single layered crusts. Teliospores compacted laterally 

 into layers, or rarely solitary within the tissues (Uredinopsis), 

 sessile ; wall usually firm, rarely with an outer gelatinous 

 1 aver. 



/ 



This family is represented in north-eastern North America 

 by eight genera, and of these seven occur in Nova Scotia. The 

 remaining genus Hyalopsora, which is confined to ferns, prob- 

 ably occurs, as H. Aspidiotus (Peck) Magn. on Phegopteris 

 Dryopteris (L.) Fee has been reported from New Hampshire, 

 and H. Polypodii on Cystopteris fragilis Bernh. from New 

 York. 



MK LAM PSORA Cast. 



Pycnia conoidal or hemispheric without ostiolar filaments, 

 hynienium flattish. Aecia without peridium or parapbysea. 

 Uredinia without peridium. Urediniospores borne singly on 

 pedicels; wall colourless, verrucose; capitate paraphyses inter- 

 mixed with the spores. Telia indehiscent in waxy layers or 

 -crusts. Teliospores one-celled, closely compacted into a single 

 layer, prismatic or ellipsoid; wall smooth, coloured. 



Both heteroecious and autoecious species belong to this 

 genus, the former only have been found in Nova Scotia. 

 Melampsora lini (Pers.) Tul. is an autoecious species which is 

 destructive to flax in the United States. 



Melampsora Bigelowii Thuem. 

 Uredo Bigelowii (Thuem.) Arth. 



0. Pycnia chiefly epiphyllous, scattered, minute, puncti- 

 form, pale yellow, inconspicuous. 



1. Aecia chiefly hypophyllous, scattered or somewhat gre- 

 garious, on whitish areas occupying part of the leaf, small, 

 round or mostly oblong, pale yellow fading to colourless, soon 



