SPECIES starting with "g"

 

Geissleria acceptata

Navicula ignota var. acceptata

  1. Valve margin elliptical
  2. Striae radiate
  3. Two rows of annulae present
  4. Stigma may be present or absent in the central area

Symmetrical biraphid - Valves are small elliptical and small. The striae are radiate. Two rows of annulae are present at the poles, but may be difficult to discern. The presence of a stigma in the central area is a variable character within the species.


Geissleria decussis

  1. Valves elliptical-lanceolate with rostrate to capitate apices
  2. Striae radiate, usually bent
  3. Central area comprised of short and long alternating striae
  4. Annulae in two rows at poles
  5. Stigma may be present in central area

Symmetrical biraphid - Valves are elliptical-lanceolate with rostrate to capitate apices. Striae are radiate and often deflected, or bent. Short and long striae alternate in the central part of the valve. The presence of a stigma in the central area is a variable feature in the species.


Geissleria ignota

  1. Valves triundulate
  2. Central area expanded
  3. Striae radiate near center, becoming parallel near apices
  4. 2-3 rows of annulae

Symmetrical biraphid - Valves triundulate with rostrate to subcapitate ends. The central area is expanded laterally with 2-4 shortened striae at the valve margin. Striae are radiate near the center of the valve, becoming parallel near the ends. Two to three rows of annulae are present at each apex of the valve.


Geissleria kriegeri

  1. Valves elliptical-lanceolate with subrostrate apices
  2. Central area small
  3. Areolae in central area absent
  4. Annulae in three or four rows at poles

Symmetrical biraphid - Valves are elliptical-lanceolate with subrostrate ends, 5.0-7.5 µm wide and 11-23 µm long. The central area is small, without isolated areolae. Striae are uniseriate, radiate, and number 16-23 in 10 µm. The annulae form three-four rows at each pole.


Geissleria lateropunctata

  1. Valves elliptical-lanceolate with narrowly rostrate or subrostrate apices
  2. Central area formed by one shortened stria at each side
  3. One to five isolated areolae in central area
  4. Annulae in three or four rows at poles

Symmetrical biraphid - Valves are elliptical-lanceolate, often slightly dorsiventral, with narrowly rostrate or subrostrate ends, 7.0-9.0 µm wide and 15-25 µm long. The central area is small, with one to five isolated areolae. Striae are radiate, and number 18-22 in 10 µm. The annulae form three-four rows at each pole.


Geissleria punctifera

  1. Valves lanceolate with broadly subrostrate apices
  2. Central area formed by one shortened stria at each side
  3. One isolated areola in central area
  4. Annulae in three rows at poles

Symmetrical biraphid - Valves are lanceolate with subrostrate broadly rounded ends, 6.0-8.5 µm wide and 16-27 µm long. The central area is small, formed by one shortened stria on each side of the valve, with an isolated stigma. Striae are radiate, 16-18 in 10 µm. The annulae form three rows at each pole.


Gomphoneis eriense

  1. Larger valves lanceolate-clavate and angular
  2. Longitudinal lines distinct
  3. Single, distinct stigma present in the central area

Asymmetrical biraphid - Larger valves are lanceolate-clavate and angular, with a slightly protracted headpole and broadly rounded footpole. The raphe is lateral and undulate. Longitudinal lines are distinct and positioned near the axial area. A single, distinct stigma is present in the central area.


Gomphoneis eriense var. angularis

  1. Valves trullate
  2. Valve length 34-67 µm
  3. Striae 10-13 in center, 14-16 at poles

Asymmetrical biraphid - Valves trullate, with broadest portion of the valve outline located towards the footpole from the central nodule. Valves are relatively small, 34-67 um in length. Striae number 10-13 in center and 14-16 at the poles.


Gomphoneis eriense var. apiculata

  1. Valves broadly lanceolate-clavate
  2. Headpole apiculate
  3. Longitudinal lines near the axial area

Asymmetrical biraphid - Valves are broadly lanceolate-clavate, with an apiculate headpole and a rounded footpole. Longitudinal lines are present on either side of the axial area, and may be indistinct in some specimens.


Gomphoneis eriense var. variabilis

  1. Valves lanceolate-clavate
  2. Longitudinal lines distinct near the axial area
  3. Striae 10-13 in the center valve, 14-16 at the poles

Asymmetrical biraphid - Valves are lanceolate-clavate. Smaller valves are elliptical-clavate, with the headpole protracted slightly. Striae are radiate at the central portion of the valve and strongly radiate at the poles. A small, barely circular central area with a single stigma is present. Longitudinal lines are distinct near the axial area, less so at the apices.


Gomphoneis geitleri

  1. Headpole broad, subrostrate
  2. Stigma present
  3. Helictoglossae distinct

Asymmetrical biraphid - Valves are clavate. An isolated stigma is present in the central area, at the end of one stria. The helictoglossae are distinct. Striae are doubly-punctate, although this feature is not discernible in LM.


Gomphoneis herculeana

Gomphoneis herculeana var. robusta
Gomphonema capitatum var. herculaneum

  1. Valves lanceolate-clavate
  2. Longitudinal lines present

Asymmetrical biraphid - Valves are large and robust, strongly lanceolate-clavate with broadly rounded headpole and narrow, rounded footpole. The axial area is narrow and straight. The central area is relatively small, irregularly rounded and bears a single stigma. The longitudinal lines are positioned approximately one-half the way between the axial area and margin.


Gomphoneis herculeana var. abundans

  1. Valves linear-clavate
  2. Longitudinal lines positioned approximately one-half the distance between the axial area and margin
  3. Length 76-160 µm, breadth 16-25 µm

Asymmetrical biraphid - Valves linear-clavate. Valve length 76-160um, valve breadth 16-25um. Longitudinal lines are positioned approximately one-half the distance between the axial area and margin.


Gomphoneis herculeana var. loweii

  1. Vlaves trullate
  2. Apices broadly rounded
  3. Striae count variable across valve

Asymmetrical biraphid - Valves broadly trullate, with broadly rounded apices. Longitudinal lines of are positioned approximately one-half the way between the axial area and margin. The striae density varies across the valve: 8-12 in 10um in the center valve, 12-14 in 10 um at the headpole, 13-16 in 10 um at the footpole.


Gomphoneis mammilla

  1. Valves distinctly clavate
  2. Striae 7-9 in 10 µm
  3. Headpole subrostrate to broadly rounded
  4. Two spines at the headpole

Asymmetrical biraphid - Valves are distinctly clavate in shape. The axial area is relatively narrow, straight, widening only slightly to form a narrowly elliptical central area with a single stigma. The raphe is lateral, weakly undulate. External proximal raphe ends are dilated. Striae are evidently doubly-punctate, radiate the length of the valve. Longitudinal lines are evident on either side of the axial area, positioned 1/5-1/4 the way from the valve margin towards the axial area. At the headpole are two conspicuous spines. The footpole bears distinct apical pore fields. Septa and pseudosepta are present at the apices.


Gomphoneis minuta

  1. Valves linear-clavate
  2. Margins convex but not tumid at the center
  3. Longitudinal lines half-way between the axial area and margin

Asymmetrical biraphid - Valves are linear-clavate, with convex margins. The margins do not become tumid at the center valve. Longitudinal lines are present, located about half-way between the axial area and margin.


Gomphoneis olivaceum

Gomphonema olivaceum

  1. Valves clavate
  2. Individual areolae not discernible
  3. Central area rectangular, bordered by shortened striae

Asymmetrical biraphid - Valves are clavate with a broadly rounded headpole and narrow footpole. The central area is bordered by shortened striae at, or near, the valve margin. Stigmoids are absent. Striae are costate and individual areolae within a stria are not discernible. Striae are radiate.


Gomphoneis pseudokunoi

  1. Valves clavate
  2. Isolated stigmoids, four in the central area
  3. Striae without resolvable areolae

Asymmetrical biraphid - Valves clavate. Axial area very narrow, straight, with filiform raphe. Central area rectangular with four isolated stigmoids. Striae costate, areolae not resolved. Apical pore fields appear as condensed striae.


Gomphoneis septa

  1. Valves lanceolate-clavate
  2. Longitudinal lines on either side of the axial area
  3. Valve tapers more strongly towards the footpole than headpole

Asymmetrical biraphid - Valves lanceolate-clavate. Valve tapers gently towards the headpole, more strongly towards the footpole especially in shorter specimens. Longitudinal lines are positioned on either side of the axial area; they are indistinct in some specimens.


Gomphoneis trullata

  1. Valves broadest below the central nodule
  2. Raphe distinctly undulate
  3. Longitudinal lines submarginal to half way between the margin and axial area
  4. Valves lanceolate-trullate

Asymmetrical biraphid - Valves are lanceolate-trullate and broadest below the central nodule. The raphe is lateral and distinctly undulate. Longitudinal lines are submarginal in larger specimens and are positioned about mid way between the margin and axial area in smaller specimens.


Gomphonema acuminatum

  1. Valves clavate
  2. Tumid at the center
  3. Two marginal constrictions
  4. Headpole broad, becomes apiculate

Asymmetrical biraphid - Valves clavate, tumid at the center with two constrictions along the margin; at the headpole the valve is broad and then becomes apiculate at the headpole, the footpole is rounded. The axial area is narrow, straight, until broadening to form an irregular central area. The raphe is lateral and undulate.


Gomphonema acuminatum var. pusillum

Gomphonema montanum var. pumila

  1. Valves linear-acute
  2. Valves biconstricted
  3. Broadest portion of the valve near the headpole

Asymmetrical biraphid - Valves linear-acute, biconstricted, with the broadest portion of the valve near the headpole. The center of the valve is slightly tumid. Punctate striae are radiate about the middle portion of the valve, becoming parallel to radiate towards the headpole, and parallel to strongly radiate at the footpole.


Gomphonema apicatum

  1. Valves acuminate-apiculate
  2. Widest portion of the valve near the apex
  3. Shortened stria opposite striae ending in stigma

Asymmetrical biraphid - Valves acuminate-apiculate and asymmetric to the transapical axis. The striae are punctate and radiate throughout to nearly parallel in the middle of the valve. Striae in the central valve are more widely spaced. On one side of the central area a stria is shortened, on the other side the central stria terminate next to the single stigma.


Gomphonema brasiliense

  1. Valves are lanceolate-clavate
  2. Axial area expanded
  3. Central nodule distinct
  4. Striae short

Asymmetrical biraphid - Valves are lanceolate-clavate, with the headpole rounded to narrowly acute. The axial area is expanded to produce a lanceolate hyaline area running the length of the valve. The central nodule is distinct and round in shape. Striae are short, radiate along the length of the valve, with each stria comprised of a single elongated areola.


Gomphonema brebissonii

Gomphonema  acuminatum var. brebissonii

  1. Valve biconstricted
  2. Headpole protracted and bluntly rounded

Asymmetrical biraphid - Valves bluntly acuminate, with the headpole protracted and bluntly rounded. The valve is biconstricted; it is broadest near the headpole, but tumid at the center of the valve. The raphe is lateral and undulate.


Gomphonema consector

  1. Valves small
  2. Headpole apiculate
  3. Striae radiate and curved

Asymmetrical biraphid - Valves are small, at less than 31 µm in length. The headpole is apiculate. Striae are radiate throughout and curved.


Gomphonema coronatum

Gomphonema  acuminatum var. coronatum

  1. Valves acuminate-apiculate
  2. Length 34-108 µm
  3. Widely tumid central portion

Asymmetrical biraphid - Valves are acuminate-apiculate, with a small, acute to blunt protracted headpole. The broadest portion of the valve is at the headpole and/or the central portion of the valve. On one side of the central area there is a shortened stria, on the opposite side the central stria terminates at the stigma.


Gomphonema elongatum

Gomphonema  acuminatum var. elongatum

  1. Headpole weakly expaned with protracted apex
  2. Central valve tumid
  3. Valves acuminate-apiculate
  4. 40-105 µm long

Asymmetrical biraphid - Valves acuminate-apiculate, with the headpole weakly expanded and protracted. The central valve is tumid. Both of the central striae are shortened, and on one side is positioned a single, isolated stigma.


Gomphonema johnsonii

  1. Valves lanceolate
  2. Apices narrow, subapiculate
  3. Striae radiate
  4. Single stigma present
  5. Central area moderately large

Asymmetrical biraphid - Gomphonema johnsonii has lanceolate valves with narrow subapiculate apices. Striae are radiate and more widely spaced near the valve center. A single stigma is present at the end of the longest central stria. The central area is moderately large.


Gomphonema kobayasii

  1. Valves linear-clavate
  2. Axial area narrow at poles, widening toward the central area
  3. Central striae more widely spaced

Asymmetrical biraphid - Valves are linear-clavate with headpole rounded and footpole narrowly rounded. The striae are strongly radiate at the footpole. The axial area is narrow at poles, widening toward the central area. The central area is broadly rectangular with shortened striae on either side. A single stigma is located in the central area.


Gomphonema louisiananum

  1. Valves lanceolate-clavate
  2. Apices narrowly rounded
  3. Striae very short

Asymmetrical biraphid - Gomphonema louisiananum has lanceolate-clavate valves with narrowly rounded apices. Striae are very short, resulting in a large lanceolate-shaped axial area. A stigma is absent.


Gomphonema mexicanum

  1. Valves elliptical-clavate
  2. Headpole slightly produced, broadly rostrate
  3. Axial area straight
  4. Stigma offset

Asymmetrical biraphid - Valves are elliptical-clavate. The headpole is slightly produced and broadly rostrate, while the footpole is rounded. The stigma opening on the inside is quite offset from the external opening. Striae are punctate, parallel to radiate and strongly radiate at the footpole. Septa and pseudosepta are present at the poles.


Gomphonema stoermeri

  1. Valves linear-lanceolate to clavate
  2. Central area asymmetric
  3. Stigma distinct

Asymmetrical biraphid - Valves are linear-lanceolate to clavate. The axial area is lanceolate. The central area is slightly asymmetric and smaller on the side bearing the stigma. Striae are parallel to radiate at the center and near the headpole, becoming more strongly radiate at the footpole.


Gomphonema ventricosum

  1. Valves lanceolate-clavate
  2. Central area irregularly elliptical
  3. Valve broadest at center

Asymmetrical biraphid - Valves are lanceolate-clavate, broadest at the center with a broadly-rounded headpole and rounded footpole. Axial area is narrowly lanceolate forming a distinct, mostly irregularly elliptical central area which possesses a single stigma. The raphe is weakly undulate and lateral. Striae are punctate, radiate to parallel. Septa are frequently observed.


Gomphosphenia grovei

  1. Valves linear-clavate
  2. Axial area broad
  3. Short striae with isolated areolae extending into axial area

Asymmetrical biraphid - Valves are linear-clavate with a broadly rounded headpole, sometime with an acute tip, footpole rounded. Striae are usually short, near the margin, but there may be isolated areolae extending towards the broad axial area. The footpole has a more dense arrangement of striae around the terminus.


Gomphosphenia lingulatiformis

  1. Valves linear-clavate to clavate
  2. Axial area lanceolate
  3. Central nodule distinct

Asymmetrical biraphid - Valves are linear-clavate to clavate. The headpole is narrowly rounded to nearly acute and the footpole is narrowly rounded. The axial area is lanceolate. Stigmata are absent. The central nodule is distinct and round. The striae are formed by a single areola, with an additional 1-2 isolated areolae towards the axial area. The striae are radiate, becoming parallel near the footpoles.