Valves are narrow and lanceolate, with broadly rounded apices. Apices are protracted in longer specimens. Striae are parallel to weakly radiate. Costae are parallel to diagonal, or slanted. Most of the costae are primary, but secondary costae are also present. Costae number 3-5 in 10 um. The axial area is linear to lanceolate, increasing in breadth as cells decrease in size. The sternum is distinct and extends into the apical porefields at both apices. Spines are present at the valve mantle-face boundary. A single rimoportula is present, most often near one end, but in some specimens the rimoportula is nearer to mid-valve.
Odontidium hyemale has been encountered throughout the western US in cool, oligotrophic subalpine streams. The valves imaged for this page were collected from streams in the foothills of the Olympic and Cascade Mountains of Washington, as well a heavily canopied alpine stream in the New Mexican Sangre de Cristos Mountains. Montane stream liverworts are a common habitat for this taxon, where it co-occurs with other costate taxa, such as Tetracyclus, Meridion, and Diatoma (Bishop and Spaulding 2015, Cantonati 2001).
C. filis mucilaginofis, geniculatis, fimplicibus tenuiffimis ferrugineis, ficcitate grifea-virefcentibus fragiliffimis: geni-geniculus obfcuris; articulis breuibus, cylindricis, cancellato-pellucidis. Roth Flora Germ. Tom. 3. Pars I. n. 22.
Bishop, I. (2017). Odontidium hyemale. In Diatoms of North America. Retrieved October 13, 2024, from https://diatoms.org/species/odontidium_hyemale
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Odontidium hyemale from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:
ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.