• Category
  • Length Range
    9.7-17.7 µm
  • Width Range
    3.7-4.7 µm
  • Striae in 10 µm
  • Synonyms
    Schizonema perpusillum (Grunow) Kuntze
    Navicula gallica var. perpusilla (Grunow) Lange-Bert.
    Diadesmis perpusilla D.G.Mann



Valves are elliptic-lanceolate to linear-lanceolate with a slight central inflation. Ends are slightly rostrate in large to mid-size individuals and broadly rounded in small individuals. The axial area is wide and lanceolate, expanding into an elliptic central area. The striae are radiate throughout. The raphe is filiform with unexpanded proximal ends.


Humidophila perpusilla favors aerial and low-light habitats, such as intermittently wettened rocks, soils, and caves. Humidophila perpusilla is widespread throughout North America, Asia, and Europe, but typically not in high abundance. This taxon frequently co-occurs with H. contenta (Lange-Bertalot et al. 2017).

Cells may be joined, valve face to valve face, in short filaments.

Original Description

Navicula perpusilla m. (Synedra perpusilla K g.?)

Navicula minuta a latere secundario lineari oblonga obtuse medio leviter tumida, nodulo centrali parvo, striis transversalibus subtillimis sub-parallelis plerumque vix conspicuis ultra 60 in 0.001’’. Longit. 0.00023-0.0007’’, latid. 0.0001-0.0002’’.

Habitat inter algas in vitreis diu asservatas. Tab. Nostr. II, Fig. 7 a, b, c, d, e, f, 400/1, g 800/1 aucta.

  • Basionym
    Navicula perpusilla
  • Author
    Grunow 1860
  • Length Range
    5.8-17.8 µm
  • Width
    2.5-5.1 µm
  • Striae in 10µm

Original Images

Humidophila Perpusilla Orig Illus
Humidophila Perpusilla Orig Desc

Cite This Page

Polaskey, M. (2018). Humidophila perpusilla. In Diatoms of North America. Retrieved June 21, 2024, from https://diatoms.org/species/humidophila-perpusilla


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