THE RUSTS OF NOVA SCOTIA. — FRASEH. 317 



no fimctiou nor any connection with the further development 

 of the fungus. They may \ye made to grow and bud in a 

 nutrient soluriou but nothing further has been obtained. It 

 may be that they had ^^ome sexual function that has l>een lost, 

 bur there is not much evidence to support this view. 



i'he pycmuui is rarely absent in the life cycle, but it only 

 occurs once, not l>eiug repeated with each generation. If the 

 aecia repeat, spermagonia only occur with the first generation. 

 If the pycnium accompanies the uredinia it does not rejieat. 

 In the case of the telios])ore it has not l)een established whether 

 it accompanies each generation or not. 



Aeciospores. 

 The mycelium, which results from the entrance of the 

 germ tube of a basidiosporc after it has produced a certain 

 number of ]\vcuia, soon develops aeciospores. Within the 

 ].)lant tissues hyphae collect together into a compact mass grow- 

 ing perpendicular to the surface of the host, and from the 

 closely crowded hyphae the spores are cut oft" in basipetal 

 succession so that they are produced in chains. At first 

 sterile cells alternate with the spore cells, but these usually 

 disappear by the time the spores are mature. The outer layer 

 of livjihae usually becomes a wall or ]~)eridium. which surrounds 

 the spore mass, and after the rupture of the ejndermis usually 

 becomes cylindrical or cupshaped. Sometimes the jieridium is 

 absent or it may be replaceil by paraphyses as in the genus 

 Phrarpnidiiuh. The s])(>re uiass with its peridium or para- 

 physes is called an aecimu or aecidinm. The spores are at 

 first polyhedral from mutual pressure, but they soon become 

 free and are then usually globose or ellipsoid in sha])i'. The 

 wall is usually colorless (deep brown in the genus 

 (lymnospornngium) with verrucose sculpturing. The rough- 

 ened wall aids the spores in adhering to the host plant. The 

 contents are chiefly orange-red or oralige-yellow and in many 

 cases soon become C(dourle^ss. Eventnally the accia rupture the 



I'noc. & TnANs. N. S. Inst. Sci.. Vol. XU. Tuans. 22. 



