• Category
  • Length Range
    67-95 µm
  • Width Range
    6.5-8.5 µm
  • Striae in 10 µm
  • Reported As
    Nitzschia obtusa (Krammer and Lange-Bertalot, 1988, plate 17, fig.1)
    Nitzschia obtusa var. multistriata (Hohn 1966, p. 489; pl. 2, fig. 7)



Valves are linear elongate with distal ends curved to opposite sides, with a slight to moderate sigmoid shape. Terminal ends are bluntly rounded. The raphe is located in a canal and positioned near the valve margin. The raphe is slightly indented toward the central valve at mid-valve. Valve at widest point is greater near the ends than in the central valve, and ranges from 7.5 to 8.5 µm. Fibulae are irregularly spaced, 6.5-8 in 10 µm. The terminal raphe fissures are distinctly recurved. The distal raphe ends terminate internally in a helictoglossa. Note that striae are not resolvable in the specimens examined, and the range of 25-40 striae in 10 µm is an estimate.

Kociolek (2004) notes that this name is not included in VanLandingham’s (1978) catalog, and that reference is given to N. kurzii Rabenhorst ex Cleve & Möller #78. Based on the International Code of Botanical Nomenclature (ICBN) (McNeill et al. 2012), the name N. kurzeana is validly published.


Collections from North America that correspond to the original description of N. kurzeana include material from from Hillsboro Canal, Southern Florida, NAWQA Sample GS027503 (ANSP GC103574a).

Original Description

N. magna, leviter sigmoidea, utroque polo obtusa, nodulis lateralibus magnis. 1 in 0,0001 m. m; valvis late linearibus, ad polos rotundato – subcapitatos cuneatis, striis transversalibus subtilissimis.

  • Author
    Rabenh. 1873
  • Length Range
    66.7-95.2 µm
  • Width
    6.8-8.3 µm
  • Striae in 10µm

Original Images

Rabenhorst  N Kurzeana1
Rabenhorst  N Kurzeana3
Rabenhorst  N Kurzeana6

Cite This Page

Spaulding, S. (2010). Nitzschia kurzeana. In Diatoms of North America. Retrieved July 22, 2018, from https://diatoms.org/species/nitzschia_kurzeana


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Nitzschia kurzeana 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.