• Category
  • Length Range
    28.1-48.6 µm
  • Width Range
    6.3-9.1 µm
  • Striae in 10 µm



Valves are linear-elliptical with rounded apices. Valve measurements: length 28.1-48.6 µm, width 6.3-9.1 µm with 12-13 striae per 10 µm. Axial area is narrow, linear and distinct; a distinct central nodule is present. The central area is asymmetrically rounded, wider on the secondary side of the valve. In LM, the raphe is filiform with enlarged proximal raphe ends deflected towards the primary side of the valve, and distal fissures are distinctly hooked towards the primary side extending from the valve face onto the mantle. Striae are radiate. The space between the striae is equal to or less than the width of the striae. Voigt faults are not easily evident. Areolae are lineate and apically aligned to form the appearance of continuous curving lines around the central area.


Original Description

Valva lineari apicibus late rotundatis. Area axiali angusta et distincta. Fissuris terminalibus raphis intortis et in eadem directione. Area centrali magna, plus aut minus ellipticali in forma. Striis lineatis distincte facientibus lineas longitudinales obscuras. Striis transversis radiatis, leniter incurvis, 13 in 10 µ. Longitudo, 33-50 µ (specimen typicum, 45.5 µ). Latitudo, 7-9 µ (specimen typicum, 8.5 µ). Striae. 12-13 in 10 µ.
Valve linear with broadly rounded ends. Axial area narrow, distinct. Terminal fissures of raphe turned to one side, and in the same direction. Central area large, more or less elliptical in shape. Striae distinctly lineate, forming indistinct longitudinal lines. Transverse striae radiate, slightly curved, 13 in 10 µ. Length, 33-50 µ (type 45.5 µ). breadth, 7-9 µ (type 8.5 µ). Striae, 12-13 in 10 µ.
This variety differs from the nominate variety in that the ends of this taxon are broadly rounded rather than bluntly acute. The central area is elliptical in this variety, whereas in the nominate variety it is rectangular. This species is related to N. pavillardi Hust. [Abh. Naturw. Ver. Bremen 31(3):635, figs 86-90, 1939]. it is similar to Navicula symmetrica Patrick (Bol. Mus. Nac. Brasil. Bot. Nov. Ser. No 2, p.5, fig.6, 1944) but differs in the striae being coarser and more coarsely lineate. Specimen illustrated-A G.C.6564A (holotype). Type locality.- Florida, Santa Rosa County, Escambia river, eight to nine miles from the mouth, R. Patrick, 1952. Distribution: United States-Florida- Santa Rosa County- Escambia river near Pensacola. TEXAS-Orange county- Sabine River near Orange.

  • Basionym
    Navicula schroeteri var. escambia
  • Author
    R.M.Patrick 1959
  • Length Range
    33-50 µm
  • Width
    7-9 µm
  • Striae in 10µm

Original Images

Naschroeteri Esc  Orig Ill
Naschroeteri Esc  Orig Descr
Original text and images reproduced with permission by Academy of Natural Sciences of Philadelphia.

EMAP Assessment

EMAP Distribution

Navicula Schroeteri Var  Escambia  Patrick 40
Map 40

Response Plots

Navicula Schroeteri Var  Escambia  Patrick

Cite This Page

Manoylov, K, and Hamilton, P. (2010). Navicula escambia. In Diatoms of North America. Retrieved June 18, 2018, from https://diatoms.org/species/navicula_escambia


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