CHAPTER VI 



CLASSIFICATION AND PHYLOGENY 



The Uredinales form a group of Fungi so closely allied that 

 they must be regarded as monophyletic. The number of species 

 considered in the present work is about 250. They may be 

 divided into five families. 



A. Impedicellat^e. 



I. Melampsoracese — Teleutospores not pedicellate, but 

 seated on a dilated hyphal cell, produced singly in the 

 tissues of the host, or compacted side by side into flat crusts, 

 1 — 4-celled. Germination by an external basidium, with 

 minute round basidiospores (about 10 /x). Uredospores ab- 

 stricted singly. iEcidia with or without a peridium. 



II. Cronartiacese — Teleutospores not pedicellate, produced 

 in chains, which are either separate or united into columnar, 

 wart-like, or lens-shaped bodies. Germination as in I. Basidio- 

 spores round, small (about 10 /x or less). 



III. Coleosporiaceoe — Teleutospores in one (or rarely two) 

 layers, forming waxy, bright-coloured crusts, not pedicellate, 

 but seated on a dilated hyphal cell, at first one-celled. Ger- 

 mination by the formation of an internal basidium of four 

 superimposed cells, each of which protrudes a sterigma and a 

 large basidiospore (about 20 /x). 



IV. Endophyllaceae — iEcidio-teleutospores surrounded by 

 a hemispherical peridium and produced from a fusion-cell, in 

 chains with intercalary cells, but germinating with an external 

 basidium. 



