ASCOCARPIC CENTRUM ONTOGENY OF SPECIES OF HYPODERMATACEAE OF CONIFERS. II

Ascocarpic studies of the ontogeny of Lophodermium nitens disclosed a type of development unlike that of all other species of Hypodermataceae occurring on conifer needles. For this reason the centrum of L. nitens is designated as Type III and is compared with Type I (Gordon, 1966). Because L. nitens produces its ascocarp in several tissues of various species of pine, the ontogeny of ascocarps in different locations is discussed and illustrated. The most significant ontogenetic feature of the ascocarp of L. nitens is a layer of hyaline cells in the primordium; this layer is meristematic and gives rise to all subsequent structures of the centrum. THIS PAPER is a sequel to the article on Types I, II, and intermediate ascocarpic centrum ontogeny of species of the Hypodermataceae (Gordon, 1966). The ascocarpic centrum development manifested by Lophodermium nitens Darker is designated as the Type III centrum for this family. The Type III centrum is more closely aligned with the Type I, as in Lophodermium juniperinum (Fries) de Not., than with the Type II as in Elytroderma deformans (Weir) Darker, or the intermediate as in Hypodermella medusa Dearness. The development of the Type III centrum, like that of the Type I, supports the theory of ascal development from pseudoparaphyses proposed by Cavara and NIollica (1907) and Arnold (1928). Before proceeding with the ontogenetic sequence of the Type III centrum, it is necessary to clarify a taxonomic problem pertaining to the Lophodermium nitens "complex." The species L. nitens was delimited by Darker (1932) as occurring only on five-needle pines (i.e., Pinus strobus, P. monticola, P. albicaulis and P. lambertiana). Tehon (1935), shifting the species to the genus Lophoderminia, listed Lophodermium nitens as also present on twoand three-needle pines (i.e., Pinus montana, P. virginiana, P. halpensis, P. ponderosa, P. rigida, and P. radiata). When L. nitens has been found on these latter six species it has almost invariably been identified as L. pinastri (Schrad.) Chev. This misidentification is undoubtedly due to the fact that both L. nitens and L. pinastri have asci and 1 Received for publication 14 February 1967. This studv is supported Fy funds from National Science Foundation grant GB-4681, Ontogeny and Cytology of the North American Species of the Hypodermataceae. The author is grateful to the following curators for providing herbarium materials without which the study would have been impossible: C. R. Benjamin, Isabelle Tavares, C. T. Rogerson, J. R. Millar, H. C. Greene, T. W. Childs, I. 'M. Lamb, C. G. Shaw, J. A. Baranayay, --AnS1 T'% r'" l ' '1 ascospores whose measurements overlap and that the ascocarp of L. pinastri occurs in the same needle tissues as that of L. nitens when the latter is found on P. banksiana. However, the two fungi can be clearly distinguished by centrum development. Lophodermium pinastri has the Type I centrum (Gordon, 1966), while L. nitens has the Type III centrum. The taxonomic problem arises from the description of the location of the ascocarp of L. nitens in the host tissue. Both Tehon (1935) and Darker (1932) describe the ascocarp as located subcuticularly (Fig. 3-8). Actually, the ascocarp of L. nitens on twoor three-needle p'nes is not subcuticular but occupies two other positions in the host tissue, depending on the pine species attacked. For instance, on Pinus ponderosa the ascocarp is completely subepidermal (Fig. 9-14), while on P. banksiana the ascocarp is subepidermal except in the region of the slit-band, where it is subcuticular2 (Fig. 15-18). The ascocarps of L. nitens, as the fungus occurs in all three possible locations, are discussed and illustrated in this