186 ENDOSPOREAE [DICTYDIUM 



at Lyme Regis, amongst typical sporangia irregular forms often occur 

 with the ribs branching and anastomosing from the base or dividing in 

 the upper half into a Cribraria-hke network (see PI. 147 c.) ; such 

 irregular forms constitute the var. anomalum of Dr. Jahn.* The 

 var. fuscum, with its well-defined cup, is a widely distributed 

 form, but is too inconstant to be regarded as a distinct species. 

 The var. alpinum has been obtained usually at higher altitudes ; 

 Dr. Sturgis has gathered it on Cheyenne Mountain, Colorado, and M.' 

 Meylan finds it abundant in the Jura Mountains, at an elevation of 

 1,000 to 1,450 m. in the autumn months ; the typical form he 

 obtains earlier in the year, from June to August, below 1,300 in 

 alt. The type of Heterodictyon mirabile Rost., from the Hollensteig 

 gorge in the Black Forest, is this variety ; the sporangia show 

 irregular basal cups, and the ribs are in many parts expanded 

 and form a loose imperfect net with broad and angular nodes ; in 

 other parts the ribs are connected by the usual delicate transverse 

 threads, and, though fewer in number and coarser than in the type, 

 are essentially of the same character. The specimen named Cribraria 

 exilis by Prof. Macbride, from Nicaragua (B.M. 1026), is a slender 

 purplish-red form of the present species, with a shallow cup connecting 

 the parallel ribs at the base. 



Hob. On dead wood. Common. — Lyme Regis, Dorset (B.M. 

 1438) ; Wanstead, Essex (B.M. 1439) ; Luton, Beds (B.M. 2769) ; 

 Glamis, Scotland (B.M. 241); France (Paris Herb.); Sweden (B.M. 

 2771); Germany (B.M. 660); Austria (B.M. 1828); Switzerland 

 (B.M. 2770); Italy (B.M. 659); Ceylon (B.M. 670); Christmas 

 Island, Java (B.M. 1440) ; Borneo (B.M. slide) ; Xew Zealand (B.M. 

 2772); Japan (B.M. 2773); Iowa (B.M. 821); Philadelphia (B.M. 

 1858) ; Antigua (B.M. 1680) ; Brazil (B.M. 2774) : var. fuscum— 

 Hants (B.M. 2775) ; Aberdeen (B.M. 2777) ; Norway (B.M. 2776) ; 

 Berlin (B.M. 2778) ; Switzerland (B.M. 2779) ; Japan (B.M. 2780) ; 

 Montreal (B.M. 2781) : var. alpinum — Jura Mountains (B.M. 2782) • 

 Colorado (B.M. 2783). 



Order II. — Liceaceae. 



Sporangia solitary, sessile or stalked ; sporangium-wall 

 cartilaginous, rarely membranous ; capillitium and columella 

 wanting. 



KEY TO THE GENERA OF LICEACEAE. 

 Sporangia sessile, subglobose or forming plasmodiocarps. 



(29) Licea. 



Fig. 37. — Licea flexuosa Pers. 



a. Group of i>lasmodiocarps. Twice natural size. 



b. Plasmodiocarp. Magnified 6 times. 



c. Spores. Magnified 200 times. 



Fig. 37. 



* A full account of the development of this species and some of the varieties to which 

 it is subject, is given by Dr. Jahn. in Ber. Deutsch. Bot. Ges., xix., pp. 97-U5 (1901). 



