392 46. LEPRARIACEAE [178. Amphiloma 



hymenium ventral and scattered over the thallus, forming an irregular, areolate 

 layer, composed of cystidia and basidia, each of the latter bearing 4 short sterig- 

 mata; spores 1 on each sterigma, brownish, non-septate, spheroidal or somewhat 

 oblong. 



The algal host is Scytonema, found in a definite layer about midway of the 

 thallus. 



A. Thallus forming semicircular or half-kidney-shaped pilei .... 1. D.irpicinum 

 A. Thallus forming an irregular layer over the substratum . . . 2. D. guadalupense 



1. Dictyonema irpicinum Mont.. Ann. Sci. Nat. Bot. III. 10:119. 1848. 

 Rhipidonema irpicinum Mont., Cent. 6:8. 1848. D.sericeum var. irpicinum 



(Mont.) Nyl. 



Pileus semicircular or half -kidney-shaped, 8-25 or more mm. across, thin and 

 membranaceous, rough and tufted or sometimes toothed, greenish gray and becom- 

 ing pale yellowish toward the uneven, scarcely fringed margin; flesh-colored to 

 pale yellow or greenish below; spores light brown, spheroidal or somewhat oblong, 

 8-12 X6-8/*. 



On trees, Florida. 



2. Dictyonema guadalupense (Rabenh.) Zahlbr., in E. & P., Nat. Pfl. 1:239. 



1907. 

 D . membranaceum var. guadalupense Rabenh.; Alq.. Hedwigia 13:7. 1874. 



Laudatea caespitose Johow. 

 Thallus forming a thin, rough and irregularly tufted, bright greenish layer over 

 the substratum; hymenium in small, irregular, furrowed patches; spores light 

 brown, spheroidal or somewhat oblong, 8-10 X 6-7 ft. 

 On trees, Florida. 



46. LEPRARIACEAE 



Thallus very rudimentary, devoid of any differentiation into layers, consisting 

 of a tangled mass of hyphae; apothecia unknown. 

 The algal host is Protococcus. 



178. Amphiloma E. Fries, in Koerb., Syst. Lich. 110. 1855. 



Thallus a tangled mass of hyphae, with no differentiation into cortex and 

 medulla, with the inclosed algal cells forming a soredioid, greenish gray to whitish, 

 mealy, friable mass, confined to moist places; attached to the substratum by 

 hyphal rhizoids; apothecia unknown. 



The algal host is Protococcus, and algal cells with parasitic fungal hyphae form- 

 ing differently appearing masses are often seen. Some of these may be early stages 

 in development of well-known lichens, and others may be other imperfect lichens. 

 Some of the masses are yellow, others greenish gray to whitish. 



1. Amphiloma lanuginosum (Hoffm.) Nyl., Act. Soc. Linn. Bord. 21 :315. 1856. 



Lichen lanuginosum Hoffm., Enum. Lich. Icon. 182. 1784. 



Thallus closely adnate, granulose, greenish gray to whitish, orbicular with plain 

 lobation at the circumference, or widely spread over the substratum and irregular 

 in form, often without the lobation; apothecia unknown. 



On rocks, bases of trees, and rarely on soil in moist, shady places, throughout 

 the United States east of the Rocky Mountains. 



