TRiCHiA.] trichiacej:. 169 
Hist. Iowa, ii., p. 132 ; Mass., Mon., p. 180. JTWcAm reniforrms 
Peck, in Rep. N. Yoi-k Mus., xxvi., p. 76 ; Mass., Mod., p 184. 
THchia Andet'sonii Rex, in Proc. Acad. Nat. Sc. Phil. (1891), 
p 395 Trichia advenula Mass., in Journ. R. Micr. boc. (i««J), 
p. 336 ; Mass., Mon., p. 181. T. heterotricMa Balf., in Grev., x 
p. 117 ; Mass., Mon., p. 174. T. loioensis Macbride, I.e., p. 133. 
a. geniiina : elaters more or less uneven from constrictions and 
irregular sweUings, with indistinct or rugged spiral thickenings. 
p. inconspicua : elaters evenly cyhndrical, usually swollen 
behind the gradually tapering pointed ends ; spiral bands distinct, 
regular, dehcate. 
■y. lutescens: sporangia yellow, subglobose; sporangitim-wall 
membranous ; elaters smooth with faint spirals. 
Plate LXI., B.—a. a, genuina, sporangia, x 20; h. sporangium-wall 
and spores, x 280 ; c. elaters, x 600 ; d. spore, x 600 (England) ; e. ^. 
incoiispicva, sporangia, x 20 ; /. elater, x 600 (Switzerland : one of Rosta- 
finski's types). 
Although the two varieties are well contrasted, intermediate forms 
are of frequent occurrence, and the variations of capillitium described 
above have on several occasions been found represented in different 
sporangia of the same group. T. inconspicua cannot therefore be re- 
garded as a distinct species. T. reniformis Peck, of which a typical 
specimen has been received from Dr. Rex, has the granular thickening 
of the sporangium-wall and the rugged irregular spirals of T. contorta 
var. genuina. A type specimen of T. Andersonii Rex is very similar to 
the last in the form of the capillitium, but the brown granules in the 
sporangium-wall are less abundant. Associated with all varieties of 
capillitium, the wall in English gatherings may either be densely 
charged with brown granules resembling the structure in PerichcBua 
corticalis, or it may be similar to that in T. Andersonii ; the difference 
in colour between spores and capillitium mentioned by Dr. Rex in his 
description of this species (Z.c.) is also a varying character, and it is 
difficult to separate the form from T. contorta. The type of T. advenula 
Mass., from Glamis (K. 1748), has the sporangium-wall charged with 
brown granular matter ; the spirals on the elaters are regular and 
distinct ; it is similar to Rostafinski's type of T. inconspicua in Strassb. 
Herb. T. heterotrichia Ball, from Currey's collection (K. 1066), appears 
to be an immature specimen of T. contorta var. genuina ; the sporangium- 
walls are almost free from granular deposits ; the elaters are 4 to 5 
diam., marked with one or three rugged or indistinct spiral bands, and 
scattered blunt spines ; the spores adhere to one another, and are very 
faintly minutely spinulose ; they measure 12 to 13 yi.. T. loioensis 
Macbride (Z.c.) agrees with T. contorta in the habit and colour of the 
sporangia, in the granular sporangium-wall, and in the spores ; the 
elaters are 3 /x diam., and, in addition to being marked with about four 
inconspicuous spiral bands, are beset with numerous slender flexuose 
spines 5 to 10 long. It appears only to have been found near Iowa 
City, and exclusively on the bark of poplar in the month of October. 
Scattered spines are occasionally met with on the elaters of T. contorta, 
and 2\ loioensis appears to be an extreme local form of this species ; 
a type specimen is in the British Museum Herb. Var. y has been 
found in Norway, September 1894, in considerable abundance, and at 
stations separated by many miles. The only characters in which it 
