| [11211] Achnanthes tibetica | Appellations de Taxon | 11211 |
| [11212] Amphora truncata | Appellations de Taxon | 11212 |
| [11213] Amphora tegetum | Appellations de Taxon | 11213 |
| [11214] Achnanthes temperei | Appellations de Taxon | 11214 |
| [11215] Attheya longicornis | Appellations de Taxon | 11215 |
| [11216] Amphora tenerrima | Appellations de Taxon | 11216 |
| [11217] Amphora tenellula | Appellations de Taxon | 11217 |
| [11218] Achnanthes tenera | Appellations de Taxon | 11218 |
| [11219] Astartiella tenuis | Appellations de Taxon | 11219 |
| [1122] Nitella | Appellations de Taxon | 1122 |
| [11220] Aneumastus tusculus f. obtusum | Appellations de Taxon | 11220 |
| [11221] Amphora tomiakae | Appellations de Taxon | 11221 |
| [11222] Actinocyclus tunkaensis | Appellations de Taxon | 11222 |
| [11223] Amphora turgida var. parallela | Appellations de Taxon | 11223 |
| [11224] Amphora turgida var. turgida | Appellations de Taxon | 11224 |
| [11225] Amphora twenteana | Appellations de Taxon | 11225 |
| [11226] Aulacodiscus acutus | Appellations de Taxon | 11226 |
| [11227] Auricula adriatica | Appellations de Taxon | 11227 |
| [11228] Aulacoseira distans var. tenella | Appellations de Taxon | 11228 |
| [11229] Auricula dubia | Appellations de Taxon | 11229 |
| [1123] Cladophoraceae | Appellations de Taxon | 1123 |
| [11230] Aulacoseira humilis | Appellations de Taxon | 11230 |
| [11232] Austariella jamalinensis | Appellations de Taxon | 11232 |
| [11233] Aulacoseira jeremiae | Appellations de Taxon | 11233 |
| [11234] Aulacodiscus kittoni var. africana | Appellations de Taxon | 11234 |
| [11235] Aulacodiscus kittonii | Appellations de Taxon | 11235 |
| [11236] Aulacoseira krammeri | Appellations de Taxon | 11236 |
| [11237] Aulacoseira lirata var. biseriata | Appellations de Taxon | 11237 |
| [11238] Aneumastus subapiculatus | Appellations de Taxon | 11238 |
| [11239] Actinocyclus subtilis | Appellations de Taxon | 11239 |
| [1124] Cladophora | Appellations de Taxon | 1124 |
| [11240] Amphora subtropica | Appellations de Taxon | 11240 |
| [11241] Achnanthes suspecta | Appellations de Taxon | 11241 |
| [11242] Anomoeoneis styriaca var. ventricosa | Appellations de Taxon | 11242 |
| [11243] Astartiella wellsiae | Appellations de Taxon | 11243 |
| [11244] Achnanthes saxatilis | Appellations de Taxon | 11244 |
| [11246] Amphora terroris | Appellations de Taxon | 11246 |
| [11247] Achnanthes teshekpukensis | Appellations de Taxon | 11247 |
| [11248] Attheya flexuosa | Appellations de Taxon | 11248 |
| [11249] Actinella thelma | Appellations de Taxon | 11249 |
| [1125] Rhizoclonium | Appellations de Taxon | 1125 |
| [11250] Amphora thromboliticola | Appellations de Taxon | 11250 |
| [11251] Amphora torontoensis | Appellations de Taxon | 11251 |
| [11252] Astartiella producta | Appellations de Taxon | 11252 |
| [11254] Alveolophora tscheremissinovae | Appellations de Taxon | 11254 |
| [11255] Attheya septentrionalis | Appellations de Taxon | 11255 |
| [11256] Astartiella glacialis | Appellations de Taxon | 11256 |
| [11257] Amphora tucumana | Appellations de Taxon | 11257 |
| [11258] Aulacodiscus argus | Appellations de Taxon | 11258 |
| [11259] Aulacoseira baicalensis | Appellations de Taxon | 11259 |