184 Transactions British Mycological Society. 
with Morenoélla, Schneepia and Hysterostomella, and he has 
added also other genera and species to the Hysteriales from 
his South American collections. In the Sylloge (Vol. u, p. 721) 
Saccardo modified his and Spegazzini’s classification, and made 
nine sections, using descriptive words with Hyalo- and Phaeo- 
as prefixes. 
Gillet (63) included the Phacidiales but not the Hysteriales in 
his work on the Discomycetes. Ellis and Everhart (64) included 
the Hysteriales in their work on North American Pyreno- 
mycetes, although they remark that they had not at first in- 
tended to do so. 
In Engler and Prantl, Pflanzenfamilien, Schroeter (65, p. 2) 
included the Hysteriineae, but not the Phacidiineae, in the 
Pyrenoasceae, but further on(p. 142) he included both these 
orders in the Discomycetes. Lindau (pp. 265-278) described the 
group, dividing it into five families. He noted that “Die 
Hysteriineae bilden eine Mittelgruppe’’ connected with the 
Phacidiaceae on one side and Lophiostomataceae on the other, 
being also similar to the Graphideae. 
Rehm (66) went over Duby’s collection and revised various 
forms. In Rabenhorst’s Kryptogamen-Flora, Die Pilze, Rehm (67) 
discussed relationships, placing the order Hysteriaceae as a 
separate group between the Discomycetes and Pyrenomy- 
cetes. He classified the genera into three families, Hysterineae, 
Hypodermieae, and Dichaenaceae, with an “‘Anhang,’’ Pseudo- | 
hysterineae Rehm, to include Acrospermum. Several genera 
previously included in the Hysteriales were removed to the 
Pezizales. Rehm at various times added to the knowledge of 
the group (68, 69). 
Boudier (7o) did not include the Hysteriales in his work on the 
Discomycetes but Schroeter(71) and Seaver (72) so classified 
them. 
Clements (73) in 1909 used the term “‘hysterothecium”’ for the 
fruit body of the Hysteriales and Graphidaceae. 
During the past few years fundamental changes in the ar- 
rangement of the Pyrenomycetes and Hysteriales have been 
proposed. Theissen and Sydow(74) included several genera, 
which had been included in Hemihysteriaceae or Hysteriaceae, 
in their work on the Dothideales, and von Hoehnel (75) in 1918 
removed several genera to the Phacidiales. In various of his 
Mycologische Fragmente von Hoehnel has given critical notes 
on genera of the Hysteriales. These notes of his and the views 
of other workers were summarized, and the results of further 
study were given, in his discussion “Ueber die Hysteria- 
ceae’’ (76). Von Hoehnel pointed out that the group had come 
to be very unnatural. He considered the Hysteriaceae to be 
