• Category
  • Length Range
    22.4-27.1 µm
  • Width Range
    5-7.5 µm
  • Striae in 10 µm
    15-19 on both valves



Valves are linear with a gibbous center and narrow, rostrate ends. Some specimens are not symmetric to the apical axis, and have ends that are slightly bent. The raphe valve has a narrow axial area and the central area is expanded to the valve margins. The proximal raphe ends are slightly deflected in one direction. The distal ends are curved strongly towards the mantle, in the opposite direction of the proximal deflection. The axial area of the rapheless valve is positioned near the valve margin. The striae are punctate and radiate on raphe valve. The striae on the rapheless valve are parallel in the center, becoming radiate with respect to the axial area and slightly curved at the apices.


Present only on two collections from Maui from a wet wall along the Hana Highway. It occurred in association with Diadesmis pantropica, Diadesmis sp., Achnanthes inflata, Geissleria ignota, Fallacia insociabilis and Nitzschia cf. clausii.

Original Description

Valves linear, swollen in the center, with narrowed rostrate ends, 20-28 µm long, 5.0-7.5 µm wide. Raphe valve with narrow axial area, with central area expanded to the valve margins (Figs 9-12, 17, 18). Raphe with proximal ends deflected slightly in one direction, with distal ends curved strongly towards mantle in opposite direction (Fig. 17). Rapheless valve with axial area near valve margin (Figs 13-16, 19), Striae punctate, radiate on raphe valve, on rapheless valve parallel in the center, becoming radiate with respect to the axial area and slightly curved at the apices, 15-19 in 10 gm on both valves. Puncta 20 in 10 µm on both valves.

  • Author
    R.L.Lowe and A.R.Sherwood 2009
  • Length Range
    20-28 µm
  • Width
    5.0-7.5 µm
  • Striae in 10µm

Original Images

Achnanthes mauiensis orig illus
Achnanthes mauiensis orig descr

Cite This Page

Lowe, R. (2011). Achnanthes mauiensis. In Diatoms of North America. Retrieved July 13, 2024, from https://diatoms.org/species/achnanthes_mauiensis


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