Diatoms of North AmericaDiatoms of North America
Return to overview

Compare Planothidium apiculatum

(R.M.Patrick) Lange-Bert. 1999

Compare

Planothidium lanceolatoides is very similar, in particular, rapheless valves are difficult to distinguish. The central area of the raphe valve of P. lanceolatoides is variable in shape and has 1-4 dash-like marks on the internal cell wall.

Other Planothidium species (P. frequentissimum, P. biporomum and P. potapovae) have a cavum, but they are much smaller. Planothidium delicatulum is also much smaller, and lacks a cavum.


LM scalebar = 10 µm
Planothidium apiculatum LM3 Planothidium apiculatum LM1 Planothidium apiculatum LM4 Planothidium apiculatum LM6 Planothidium apiculatum LM2 Planothidium apiculatum LM5 Planothidium apiculatum LM7
Length Range
25-31 µm
Width Range
9.0-12.7 µm
Striae in 10 µm
10-12

Planothidium lanceolatoides

(Sovereign) Lange-Bert. 1999

Planothidium lanceolatoide LM1 Planothidium lanceolatoide LM2 Planothidium lanceolatoide LM4 Planothidium lanceolatoide LM3 Planothidium lanceolatoide LM7 Planothidium lanceolatoide LM6 Planothidium lanceolatoide LM5
Length Range
17-36 µm
Width Range
9-13 µm
Striae in 10 µm
11-14

Planothidium frequentissimum

(Lange-Bert. in Krammer and Lange-Bert.) Lange-Bert. 1999

Gs119780 1 Ed Planothidium frequentissimum LM3 Planothidium frequentissimum LM2 Mo000019 1A Ed 5 Planothidium frequentissimum LM1 Gs181995 1B Ed Mo000019 Plfreq 1B Ed
Length Range
5-17 µm
Width Range
3-6 µm
Striae in 10 µm
13-18

Planothidium delicatulum

(Kütz.) Round and Bukht. 1996

Gs181995 2A Gc112144B Nrsa0167 Pldelic1 Gs134565 1A Gs134565 3 1 Gs134565 6 Gc8031 Sabine Pldel1B
Length Range
12-20 µm
Width Range
4.7-7.5 µm
Striae in 10 µm
13-15

Planothidium potapovae

C.E.Wetzel and Ector 2019

Gsn23403 Plrostr 3 Gsn23403 Plrostr 2 Gsn23403 Plrostr 5 Gc48893A 1A
Length Range
11.0-17.5 µm
Width Range
5.0-6.0 µm
Striae in 10 µm
11-13

Planothidium biporomum

(M.H.Hohn and Hellerman) Lange-Bert. 1999

Planothidium bipororum LM3 Planothidium bipororum LM1 Planothidium bipororum LM4
Length Range
12-25 µm
Width Range
5.4-7.0 µm
Striae in 10 µm
12-15