Diana G. Horton

Vegetational changes in Western Illinois during the onset of Late Wisconsinan glaciation

Peats and silts near Biggsville, western Illinois, have yielded the most detailed paleoecological record available in the midcontinent for the time when Late-Wisconsinan glaciers began to advance. These deposits were analyzed for pollen, vascular-plant macrofossils, bryophytes, insects, and stratigraphy, and date from 28 000 to 22 000 BP. Upland vegetation was a Picea-Pinus banksiana forest from 27 900 to 26 600 BP. From 26 600 to 22 700 BP, Picea and Larix laricina were the dominant trees, and Pinus had all but disappeared. This change probably reflects a climatic cooling when glaciers began to advance into the Midwest. A decrease in Picea pollen percentages and total pollen accumulation rate, an increase in Cyperaceae and other non-arboreal pollen, and the appearance of Selaginella selaginoides after 22 700 BP suggest a further cooling, and indicate an open environment as Late-Wisconsinan glaciers advanced into Illinois. Locally, a small pond, which accumulated organic silts and supported a rich aquatic flora, was present from 27 900 to 27 000 BP. Peatlands surrounding the pond were dominated by rich fen bryophytes and a diverse wetland herbaceous flora. A Picea mariana muskeg replaced the pond and fen between 27 000 and 23 500 BP, the peat became increasingly woody, and the wetland became dominated by P. mariana, Larix laricina, and Betula glandulosa. Peat deposition ceased by 23 500 BP when loess accumulation began; small ponds again were present in the lowland, but they supported only a sparse aquatic flora. By 21 400 BP, the basal loess and paleosol had capped the peats, and subsequently rapid loess deposition buried all previous deposits.

Plant and insect remains from the Wisconsinan interstadial/stadial transition at Wedron, north-central Illinois

Abstract Organic material exposed within a small swale fill in Pit 6 of the Wedron Silica Sand Co. near Wedron in LaSalle County, Illinois, includes well-preserved pollen, plant macrofossils, and insect remains. This material occurs in slackwater sediment in the lower part of the Peddicord Formation, which was deposited as existing valleys were dammed by fluvial aggradation during the initial late Wisconsinan advance of Laurentide ice into the Wedron area. Wood from the organic horizon has a radiocarbon age of 21,460 ± 470 yr B.P. (ISGS-1486). The pollen spectrum is dominated by Picea, Pinus , and Cyperaceae. Plant macrofossils comprise a mix of boreal-forest taxa, including Picea, Larix laricina , and the moss Campylium stellatum ; subarctic species including Betula glandulosa, Empetrum nigrum , and Selaginella selaginoides ; along with the predominantly arctic Vaccinium uliginosum var. alpinum, Dryas integrifolia , and Rhododendron lapponicum . The insect fauna contains the western montane ground beetle Opisthius richardsoni ; several arctic-subarctic ground beetles including Diacheila polita, Helophorus sibiricus , and Pterostichus (Cryobius) caribou ; and a diverse assemblage of insects that today inhabit the boreal forest. We interpret the biotic record to record a phase in the transition from closed boreal forest to open tundra as climatic conditions deteriorated in advance of continental glaciation.

Mid-Wisconsinan stratigraphy and paleoenvironments at the St. Charles site in south-central Iowa

A sequence of loess-mantled sediments exposed along Clanton Creek provides the first evidence of fluvial, pedologic, and biotic environments before the last glacial maximum in south-central Iowa. Two fining-upward fluvial sequences, one inset into the other, are exposed. Radiocarbon ages indicate that the alluvial fills are about 34,000 yr old. Basal gravel in the oldest fill contains well-preserved mammoth ( Mammuthus ) bones. Sparse seeds from this horizon suggest weedy flood-plain conditions. The younger alluvial fill contains well-preserved pollen, plant macrofossils, and insects. The pollen is dominated by nonarboreal taxa and Pinus , suggesting a prairie border or savanna environment. Vascular-plant and bryophyte macofossils indicate a variety of aquatic and marsh environments on the flood plain. Insects are mostly sympatric in mixed conifer and hardwood forest that extends along latitude 47° to 49° between eastern North Dakota and New England, but forest beetles are rare, and the fauna is dominated by openground forms. The site is interpreted as an open flood plain dotted with marshes and oxbow lakes; it was surrounded by open woodland or savanna similar to that in north-eastern North Dakota at present. July temperatures at the St. Charles site were probably 3 to 5 C° cooler than those at present. The pre-loess stratigraphy of the site differs markedly from that of upland sites and demonstrates that correlation between upland and lowland sequences cannot be done without adequate dating.

Late Wisconsinan-early Holocene riparian paleoenvironment in southeastern Iowa

The lithostratigraphy, radiocarbon ages, and pollen and plant macrofossil assemblages in a low terrace on the Iowa River beyond the Wisconsinan glacial boundary reveal regional alluvial relationships and indicate that valleys were important corridors during vegetational change in the Midwest. Basal pebbly sands probably represent a valley train from a central Iowa glacial advance ∼25,000 to ∼21,000 yr B.P. Overlying organic silts indicate low energy conditions from ∼21,000 to ∼15,000 yr B.P. Pebbly sands of an upper valley train were deposited from ∼14,000 yr B.P. until 10,000 yr B.P., about 1,500 yr after the Des Moines Lobe had retreated out of the Iowa River Basin. Pollen and plant macrofossils from the top of the upper pebbly sands indicate that the area was covered by mixed conifer-hardwood forest taxa whose pollen percentages do not match those predicted by models of vegetational change in eastern North America. Boreal elements with general distribution over 500 km to the north at 10,000 yr B.P. persisted in peatland habitats. The valley environment contained a variety of edaphic and microctimatic conditions that supported diverse plant communities. During glacial-interglacial transitions, medium to large valleys served as migration corridors for plant taxa and harbored riparian communities without modern analogs.

Bryophytes New to Alberta, Yukon Territory and Northwest Territories, Canada

Seventeen mosses and four hepatics are reported for the first time from the Yukon Territory, 22 mosses and one hepatic from Alberta and two mosses from the Northwest Territories. Sporophytes were found for the second time on Cyrtomnium hymenophyllum (B.S.G.) Holm. The North Amer- ican distributions of Oedipodium griffithianum (Dicks.) Schwaegr. and Mar- supella revoluta (Nees) Dum. are mapped. Significant range extensions are included for Seligeria oelandica C.Jens. & Medel., S. calcarea (Hedw.) B.S.G. and Isopterygium elegans (Brid.) Lindb. As a result of extensive field work in northwestern Canada over the past few years, we have collected 46 species not previously reported from particular provinces or territories. We note 17 mosses and four hepatics as new to the Yukon Territory, 22 mosses and one hepatic as new to Alberta and two moss species as new to the North- west Territories. Sporophytes of Cyrtomnium hymenophyllum are reported for the first time in North America. A few species of particular interest, which have been reported elsewhere, are also included in our discussion. Such taxa are indicated by an asterisk. The literature on mosses reported from the Yukon Territory was summarized by Vitt (1974a). At that time only 218 species were known from the Territory. Since then, several authors have reported on taxa new to the area. Steere and Smith (1975) re- ported Oligotrichumfalcatum; Steere and Murray (1976) described Andreaeobryum macrosporum, citing a Yukon locality among their records; Horton and Murray (1976) reported two new Encalypta species; Vitt (1976b) presented records of 96 new mosses (93 species) from the Ogilvie Mountains; Douglas and Vitt (1976) reported 16 taxa (10 species) new from the Kluane area; Bird et al. (1977) listed six species from the northern portions; Vitt and Horton (1978) added 21 more from various localities; Frahm and Vitt (1978) reported Campylopus schimperi from the Richardson Moun- tains; Steere and Scotter (1978a) added 18 species from the British Mountains; and Steere and Scotter (1978b) recorded 13 species as new from the southeastern area. With the inclusion of the 17 species reported herein, the moss flora of the Yukon Territory, as presently known, consists of 401 species (424 taxa). The hepatic flora of the Yukon Territory is less well known than that of the mosses. Hong and Vitt (1977) recorded, from the literature and collections, 91 species of he- patics from the Yukon; Horton (1977) reported on 2 phytogeographically interesting species from the Keele Peak area; Vitt and Horton reported an additional species in 1978, while Steere and Scotter reported 5 species new from the British Mountains

Encalypta vittiana sp. nov. and E. flowersiana sp. nov. from North America

Two North American species are described: Encalypta vittiana from Alaska, Yukon Territory and western Northwest Territories and E. flowersiana from Guatemala and Haiti. Each is closely related to a taxon belonging to the E. rhaptocarpa-E. vulgaris complex: E. vittiana to E. rhaptocarpa Schwaegr., from which it is distinguished by precisely fringed calyptrae, and E. flowersiana to E. spathulata C.Miill., from which it is distinguished by muticous leaves and spores with vermiform protuberances on the distal surface. On the basis of morphological discontinuity and, in the case of E. flowersiana, geographical isolation, both E. vittiana and E. flowersiana are given recognition as species. The markedly restricted distribution of E. vittiana is similar to that of both endemic and circumarctic-alpine species of mosses and may be a result of Pleistocene glaciation. It is hypothesized that E. flowersiana may have evolved in geographic isolation from E. spathulata. The narrow geographical range of E. flowersiana may be a function of altitudinal

Bryochenea (Musci; Thuidiaceae) is Cyrto-hypnum (Thuidiaceae), but B. sachalinensis is Echinophyllum (Thuidiaceae), a New Genus from the Pacific Rim

Abstract The genus Bryochenea is evaluated by a study of morphological characters from type and other herbarium specimens. The type species, B. ciliata, is taxonomically synonymous with Cyrto-hypnum vestitissimum; therefore, Bryochenea is synonymous with Cyrto-hypnum. Bryochenea sachalinensis, the only other species, has been treated as Helodium sachalinense by most authors. An evaluation of the generic and familial positions of B. sachalinensis, based on comparisons with Helodium and 12 other hypnalean genera, indicates that B. sachalinensis is sufficiently distinct to warrant generic rank. A monotypic genus, Echinophyllum, is described and the new combination, E. sachalinensis, is made. The combination of dry branch leaves that are catenulate, short and strongly unipapillose leaf cells, and lanceolate pseudoparaphyllia with laciniate margins and papillose basal cells support inclusion of Echinophyllum in the Thuidiaceae; however, the elongate paraphyllial cells and elongate apical cells of branch leaves are incongruent with Thuidiaceae and instead suggest closer affinity to Helodiaceae, Hylocomiaceae, or Leskeaceae. The closest match among these alternatives is with Helodiaceae, but there are sufficient differences in habitat, leaf areolation, and pseudoparaphyllia that the alignment with Thuidiaceae is considered preferable.

Encalyptaceae Americanae Exsiccatae: An Annotated Guide to Fasciculus I (Numbers 1-10)1

Specimens of Encalyptaceae from North and South America will be distributed to 50 herbaria as Encalyptaceae Americanae Exsiccatae. Fas- ciculus No. 1 contains 10 numbers. Two genera, Bryobrittonia Williams and Encalypta Schreb. ex Hedw., comprise the Encalyptaceae. The long-cylindric, campanulate calyptra exemplifies the family. Bulging, but almost smooth, up- per leaf cell walls of Bryobrittonia are quite distinct from the bulging and highly modified ones of Encalypta. One of the first descriptions and figures of a species of Encalypta was published by Petiver in 1695. Later, Bridel and Hedwig described species of Encalypta, but Bridel was the first to recognize and establish the taxonomic significance of the distinctive calyptra. The En- calyptaceae has most often been considered closely related to the Pottiaceae. Distributional and ecological data on E. brevipes Schljak. and E. mutica Hag. are presented. The distribution of E. longicolla Bruch in North America is mapped. Chromosome numbers of n = 12 and n = 13 are reported for E. mutica and E. longicolla, respectively. Two specimens of E. spathulata C.Muill., which has recently been reported to occur in North America, are contained in this first fascicle. Distinguishing features of two closely related species, E. ciliata Hedw. and E. brevicolla (B.S.G.) Bruch ex Aongstr., are discussed. The essential similarity in the cell wall structure of Bryobrittonia longipes (Mitt.) Horton to that of species of Encalypta is illustrated.

A Computer Program for Printing Herbarium Labels

A computer program which prints herbarium labels has been constructed. Individual labels consist of a maximum of 12 lines, each of 40 spaces. However, labels with varying amounts of information can be printed. A cost analysis indicates that the computer printed labels are approximately half the cost and are of superior or equivalent quality when compared with xerox duplicated or magnetic-card typed labels. This program is available from the authors.

Lectotypification of Encalypta affinis (Musci): Maintenance of Continuity between Epithet and Taxonomic Concept

The taxonomic concept of E. affinis is well established historically and the epithet affJinis has been fairly consistently applied to this taxon, particularly recently. Even though the original description and illustrations were, at least in part, based upon plants of E. affinis, the potential type specimens presently in the original authors herbarium consist of another distinct, and probably only distantly related species, E. alpina. As the specimen in the collectors herbarium consists of both E. affinis and E. alpina, it is concluded that the original description was based upon a mixed collection, a portion of which has since been removed. Therefore, E. affinis is lectotypified in the collectors herbarium in order to maintain the continuity established between the taxonomic concept and the epithet, in accordance with Recommendation 7B of the ICBN.