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The fungi here described were all collected in Iowa with the single exception of Grandinia granulosa Fries. These have more than local interest since the occurrence of several species has ap? parently not previously been reported from the United States. The published records of resupinate species of the Hydnaceae in this country, however, are not believed to be a fair index of their frequency or distribution. Many of the little known species are common in Iowa. The vast collections of undetermined material

Polyporus biennis and its varietal segregates possess quite variable characteristics. They have masqueraded among the poroid Boleti and Polypori, the labyrinthine Daedaleae and the echinoid Sistotremae, not to mention that group of contortionists, the genus Abortiporus, created by Murrill for the reception of a member of this group. They have finally come to rest, as appears most appropriate, in the genus Polyporus. Of the five fungi considered here Polyporus biennis, apparently, has not been collected in North America, but is typically European. The remaining four are varieties of this species. Though the first of these has been reported from the United States this was without justification. Our present knowledge indicates the last three to be wholly American in their distribution. Bulliard (1789) first described and figured Polyporus biennis, and placed it in the genus Boletus. A few years later Persoon (1797) conceived a need for the genus Sistotrema, and subsequently (1801) included Bulliard's species within this group. As first instituted Sistotrema is located between the genera Boletus and Poria, and contained but two species, S. confluens, based upon Hydnum sublamellosum Bull., and S. cinereum, based upon Boletus unicolor Bull. With his customary naivete Persoon changes these specific names without offering excuse or reason. In his "Synopsis" Persoon extends Sistotrema to include twelve species. These are about evenly divided between forms gleaned from the genus Hydnum, and near relatives, and from Boletus as interpreted by Bulliard. In an appended foot-note Persoon says briefly, "Intermedium genus est inter Boletum et Hydnum." Persoon considered Sistotrema as a repository for certain species which he believed transitional in nature and properly located between the Polyporaceae and Hydnaceae.

(1913). Type Studies in the Hydnaceae—V. the Genus Hydnellum. Mycologia: Vol. 5, No. 4, pp. 194-205.

(1912). Type Studies in the Hydnaceae—I. The Genus Manina. Mycologia: Vol. 4, No. 5, pp. 271-278.

The family Hydnaceae, as ordinarily defined, is held to include all autobasidiomycetes in which the hymenium is borne upon downward directed spines, warts or folds. As thus defined most of the genera and species are clearly separated from those of re? lated families. Intermediate forms do occur, however, grading into the Polyporaceae on the one hand and the Thelephoraceae on the other. This fact has influenced various attempts to make the boundaries of the family more distinct. Since the time of Fries, our knowledge of the internal structure and reproduction of these fungi has been greatly increased and it has been necessary to make many changes in taxonomic treatment. The lack of agreement in current literature as to what constitutes the most precise or convenient classification is due largely to our still meager knowl? edge of the natural relationships among these fungi. The family has been insufficiently studied and, therefore, any scheme of classification applied to it must be regarded as tentative. The removal of certain genera and species apparently related to the Polyporaceae but included in the Hydnaceae of Fries and his predecessors was suggested first in 1821 by the work of S. F. Gray.1 He erected the Sistotremideae on Sistotrema, Cerrena and Xylodon, and characterized the new family as " thallus leatherlike; hymenium at first meandering, porous, becoming toothed; teeth lamellar, torn." In 1879 Karsten transferred Irpex, Sistotrema and Phlebia to the Polyporaceae. Patouillard in 1900 included Phlebia, Hydnochaete, Lopharia, Sistotrema and species of Irpex among the polypores. Weir and Hubert (1918) comment on the daedaloid character of the young sporophore of Echinodontium.

1. Narrowly reflexed, sometimes resupinate, thick, not cracking; clamp con? nections numerous; spores 5-7 X 3-4 ^.3. R. pallidum. 1. Resupinate, adnate, varying in thickness, sometimes cracking; clamp con? nections present or absent; spores usually larger.. (2) 2. Cracking; clamp connections few or absent; spores 6-8 X 3-4 ^ 2. R. quercinum. 2. Generally not cracking; clamp connections numerous; spores 8 -12 X 3-4 m, curved. 1. R. orbiculare.

(1914). Type Studies in the Hydnaceae—VII. The Genera Asterodon and Hydnochaete. Mycologia: Vol. 6, No. 5, pp. 231-234.

Climacodon P. Karsten, Rev. Myc. 31: 20. I88I. The genus Creolophus Karst. was established on Hydnum corrugatum Fr. as the type. No type specimen of this species was found at Upsala bult several specimens in the herbarium collected by P. A. Karsten, E. Th. Fries, and Fr. Kjellman in Sweden and Finland were referred to this species. All of these agree perfectly with Fries's description and may be regarded as authentic representatives of the species. They do not appear to be generically different from H. septentrionale Fr., having much the same form, color, and fleshy or subfleshy substance. The species has not yet been positively recognized as an American form. Climacodon Karst. was established on Hydnum septentrionale Fr. and is, therefore, a metonym of Creolophus. We have hitherto included the species of this genus in the genus Steccherinum. The peculiar fleshy or subfleshy character of the substance of these plants, so strikingly different from the dry and tough fibrous character of typical Steccherrinum, has convinced us that they should be maintained in a separate genus for which a name has already been provided by Prof. Karsten.

Descriptions of twelve taxa in the genus Hydnum are provided, with keys for their determination. One new species is proposed. Macroscopic illustrations, as well as photomicrographs of spores are pr...

Odontia is the only strictly resupinate genus of the Hydnaceae characterized by the presence of cystidia. Steccherinum ochraceum, S. lacticolor and 5\ setulosum have cystidia and may occur resupinate but these can be distinguished generally by their more coriaceous texture and larger size. Cystidia are readily separated from gloeocystidia, setae and conducting organs but often are distinguished with difficulty from the sterile hymenial organs known as paraphyses. Sterile hymenial organs which are readily distinguished from basidia are here treated as cystidia. A cystidium is generally regarded as the specialized end of an undifferentiated hypha and typically has thickened walls, no conspicuous content and is often incrusted with granular material (Overholts, 1929). It seems unwise arbitrarily to distinguish between the unspecialized hyphae and typical cystidia projecting at the crest of the tooth in many species of Odontia, particularly since this character may vary in a given species.

Students of our Hydnaceae have frequently emphasized the need of more complete field notes upon our American species. Banker, in his revision of the North American Hydnaceae, speaks repeatedly of the lack of definite field notes in regard to our species and the resultant uncertainty in regard to the status of some of them. As a rule our species are quite rare, Banker for example having been able in six years careful watching to find but two specimens of Sarcodon imbricatus. In my collecting grounds at Asheville, North Carolina, on the contrary, they occur at times in abundance, giving ample opportunity for study. Some of my observations made there upon the scaly species of Hydnaceae seem to explain some of the difficulties with this group and for that reason to merit publication. The most abundant Asheville species is the one commonly referred to Sarcodon imbricatus (L.) Karst., though considered by some rather Sarcodon subsquamosus. This was regularly found in August and early September, and aside from the growth changes mentioned below, was quite constant. Its appearance is well shown in Fig. 1. The fleshy pileus was light-grayish-brown to dark-brown, with conspicuous, superficial, floccose scales which were larger and more prominent at the center. Along with this typical form were found also other forms which from the circumstances of their growth were taken for older forms of the same