188 BASIDIOMYCETES. 



that the outer peridium splits star-like and folds back, elevating the fruit 

 body in such a way as to aid in the distribution of the spores. 



The Basidiomycetes also include the woody fungi which occur on the 

 trunks of trees and are often the source of great damage by causing heart 

 rot. The number of such species found in Bermuda was surprisingly small, 

 perhaps on account of the small number of kinds of native host plants. 



Order 11. USTILAGINALES. 



The smuts, which belong to this order, are often included with the 

 lower Basidiomycetes. One species has been found in Bermuda, Ustilago 

 Zeae (Beckm.) Unger, a very destructive parasite. 



Order 12. UREDINALES. 



Some of the species of plant rusts belonging to the present order oc- 

 curring in the islands are: Nigredo proeminens (DC) Arthur occurring on 

 leaves of Poinsetta and various species of Chamaesyce, and Nigredo Medi- 

 caginis (Pass.) Arthur on the leaves of Medicago denticulata. Other 

 species are : Puccinia Lantanae Farlow, Puccinia DicJwndrae Mont., Puc- 

 cinia Cladii Ellis & Tracy, Puccinia Polygoni-amphibii Pers. and Puccinia 

 purpurea Cooke. Tranzschelia punctata (Pers.) Arthur occurs as a para- 

 site on the leaves of cultivated peach. 



Order 13. AGARICALES. 



This order contains the edible mushrooms. Among the endemic 

 species are : Agaricus alphitophorus Berk., Agaricus helictus Berk., Maras- 

 mius bermudensis Berk., Marasmius Sabali Berk., Marasmius praedecur- 

 rens Murrill, Pleurotopsis niduliformis Murrill and Tyromyces graminicola 

 Murrill. In all thirty species of the order have been recorded. 



Order 14. AURICULARIALES. 



One endemic species belonging to this order has been collected, Hirne- 

 ola coffcicolor Berk. 



Order 15. LYCOPERDALES. 



The earthstar named above is the only representative of this order. 



Order 16. PHALLALES. 



A single species belonging to the genus Clathrus has been collected 

 but was in such poor state of preservation that it could not be determined. 



Imperfect Fungi. 



In addition to the main groups of fungi, there are a large number of 

 species which are thought to represent stages in the life cycles of other 

 fungi, especially the Ascomyeetes. These are included in the group com- 

 monly known as the Imperfect Fungi, since their histories are imperfectly 

 known. Fourteen species of such fungi collected in Bermuda have been 

 named. Many of these occur as parasites and are the cause of serious leaf 

 and stem injury. One species, Helminthosporium Ravenelii, forms its 



