British Gastromycetes . 39 
Hysterangium Thwaitesii , B. and Br., Ann. Nat. Hist, 
ser. 2, ii, p. 267 (1848); TuL, Fung. Hypog. p. 82; Cooke, 
Hdbk. n. 1051 ; Sacc., Syll. vii, p. 156. 
Splanchnomyces membranaceus , Corda, Ic. Fung, v, vi ? 
Leigh Wood, Bristol ! (Type in Herb. Kew.) 
Mycelium white, fibrillose, not much to form membranous 
expansions, spreading for some distance. Sporangium globose 
or slightly irregular, white, slightly silky, when rubbed or 
exposed to the air assuming a rufous tinge. Peridium 
membranous, not so thick as in H. nephriticum , though as in 
that species it sometimes separates when dry ; rufous when 
divided. Cells brownish olive. Spores oblong, apiculate, 
differently shaped from those of the other species, and com- 
parable only with those of H. membranaceum , Corda (Berk.). 
Rhizopogon, Tul. 
Peridium thick, subcoriaceous, or sub-membranaceous, 
continuous or cracked and subevanescent, with vein-like 
branched fibres traversing its surface ; substance of gleba firm, 
cavities distinct, at first empty ; spores smooth. 
Rhizopogon , Tub, Giorn. Bot, Ital. ii. p. 56; Sacc., Syll. 
vii, p. 161. 
The cord-like branched mycelium adnate to the surface of 
the peridium is characteristic of the above genus, which 
resembles Hysterangium in the smooth eliptical spores. 
Rhizopogon rubeseens, Tul. (Fig. 7). Ovate or globose, 
with a long slender rooting mycelium, at first white and silky, 
becoming reddish when exposed to the air, when mature yellow 
or olive ; flesh yellow, then pale olive ; cells numerous, small, 
irregular; spores elliptic-oblong, almost colourless, smooth, 
11 X4-5m. 
Rhizopogon rubeseens , Tub, Giorn. Bot. Ital. ii, 58 (excl. 
syn. Friesii); B. and Br., Ann. Nat. Hist, xviii, 76; Berk., 
Outl. 294; Cke., Hdbk. n. 1052; Tub, Fung. Hypog. 89, t. 
xi, f. iv, t. ii, f. 1 ; Sacc. Syll., vii, p. 161. 
