Eleocharis compressa × Eleocharis erythropoda, a new natural hybrid spike rush from Ontario

Partially sterile plants from eastern Ontario are identified as Eleocharis compressa × Eleocharis erythropoda on the basis of intermediacy in perianth bristle length, tubercle shape, achene surface roughness, length of rhizome internodes, culm cross-section shape, and length of terminal lobes of scales. Both putative parents occurred with the hybrid plants. The hybrid plants had tardily deciduous scales and either bifid or trifid styles. They superficially resemble E. erythropoda most closely but differ markedly in their scaly rhizomes with shorter internodes 3.8 – 7 mm long. They are most readily distinguished from E. compressa by their elliptic or broadly rectangular culm cross sections and some perianth bristles exceeding 0.5 mm in length. This putative hybrid involves taxa in different subseries that would normally be regarded as too distantly related to permit hybridization. Key words: Eleocharis compressa, Eleocharis erythropoda, Cyperaceae, hybrid, taxonomy, classification.

Wetland Treatment of Pulp Mill Wastewater

Ten wetland ponds, each 1430 m2 (1/3 acre) in area are being utilized to evaluate the treatment of wastewater from a pulp mill. The ponds are being operated at a depth of 46 cm (18″) and detention times are 2 and 10 days. Six of the ponds have been planted to cattails (Typha latifolia) and three to bulrush (Scirpus acutus). One of the ponds is filled with large (150 mm) stone to compare a subsurface non-plant system. In 24 stock tanks, 8 aquatic plant species (Cattail, Hardstem Bulrush, Bolander's Rush, Common Spike Rush, Water Mannagrass, Beaked Sedge, Water Parsley and Yellow Pond Lily) are being grown to evaluate the effect of plants in the wetland treatment of wastewater. These same species are being evaluated in a larger area for competitiveness and hardiness in the wastewater. The ponds were planted in the winter of 1990/91. Results of this work on treatment of biochemical oxygen demand, solids and colour removal will be reported. Removals are in the range of 55%, 70% and less than 5% for the three parameters, respectively.

EVOLUTION OF LIMOTETTIX SAHLBERG (HOMOPTERA: CICADELLIDAE) IN PEATLANDS, WITH DESCRIPTIONS OF NEW TAXA

The world species of Limotettix Sahlberg are reviewed, and 13 new Nearctic species are described: in the typical subgenus — L. conservatus; in the new subgenus Dryola — L. elegans, L. minuendus; in subgenus Neodrylix — L. urnura; in subgenus Ophiolix — L. nigristriatus, L. pseudosphagneticus, L. xanthus; and in subgenus Scleroracus — L. brooksi, L. medleri, L. obesura, L. scudderi, L. strictus, and L. zacki. Limotettix (L.) emeljanovi is proposed to replace L. luteolus Emel'janov, 1962, nec L. (Scleroracus) luteolus (Sleesman, 1930). The 80 known world species are arranged phylogenetically. From this analysis the genus evidently evolved in the New World from swale and fen inhabiting ancestors that fed on spike-rush. Their bog-inhabiting descendents fed on various rushes and sedges, but apomorphic lineages transferred to ericaceous plants. Adaptation to ericaceous plants permitted invasion of drier habitats, with subsequent radiation on other semiwoody plants, principally Asteraceae and Symphoricarpos.

Rhizome architecture for dispersal in Eleocharis palustris

The rhizome architecture of a population of the spike rush, Eleocharis palustris (L.) R. & S., was examined. Its rhizomes were found to display remarkably little branching. Furthermore, the rhizomes turned very little from year to year in their direction of growth. In this paper, these observations are documented and possible evolutionary advantages of such an architecture are explored. Particular emphasis is placed on the hypothesis that the fitness of an individual clone could be enhanced by such a strategy through an increase in the probability of escape from a crowded seedbed.

Description and relationships of a new root-knot nematode, Meloidogyne sewelli n.sp. (Nematoda: Meloidogynidae) from Canada and a new host record for the genus

A new root-knot nematode from Quebec, Canada, Meloidogyne sewelli n.sp. is described and illustrated from spike-rush, Eleocharis acicularis (L.) R &S. The most distinctive characters of the infective larva are its body length of 505–553 μm, posterior position of the dorsal esophageal gland orifice at 7–8 μm, and the presence of an inflated rectum. The egg sac is larger than the female and always contained within the root gall. Perineal pattern of the female is weakly etched or indistinct and the terminus of the male tail is distinctively subdigitate. The above type host plant is a new host record for root-knot nematodes. Relationships of the new species to five of the most closely related species are discussed and a taxonomic key and table of diagnostic characters to their infective larvae are presented.