| BGCI European Threatened Taxon starting with C | Number of
accessions |
| Calamagrostis scotica Druce | 1 |
| Calendula suffruticosa Vahl subsp. maritima (Guss.) Meikle | 3 |
| Callianthemum kernerianum Freyn ex A.Kern. | 1 |
| Callitriche pulchra Schotsman | 1 |
| Campanula columnaris Contandr., Quézel & Zaffran | 1 |
| Campanula cymaea | 1 |
| Campanula hierapetrae Rech. f. | 4 |
| Campanula incurva Aucher ex A. DC. | 11 |
| Campanula laciniata L. | 8 |
| Campanula merxmuelleri Phitos | 1 |
| Campanula raineri Perp. | 8 |
| Campanula rupestris Sm. | 4 |
| Caralluma munbyana (Decne. ex Munby) N. E. Brown subsp. hispanica (Coincy) M. B. Crespo & Mateo | 1 |
| Carduus myriacanthus Salzm. ex DC. | 3 |
| Carex camposii Boiss. & Reuter | 2 |
| Carex durieui Steud. ex Kunze | 3 |
| Carlina diae (Rech. fil.) Meusel & Kastner | 4 |
| Castrilanthemum debeauxii (Degen, Hervier & E.Rev.) R.Vogt & Oberpr. | 1 |
| Cedrus brevifolia (Hooker fil.) Henry | 6 |
| Centaurea akamantis T. Georgiadis & G. Hadjikyriakou | 9 |
| Centaurea baldaccii Degen ex Halácsy | 1 |
| Centaurea bombycina Boiss. ex DC. | 7 |
| Centaurea borjae Valdés Berm. & Rivas Goday | 2 |
| Centaurea carratracensis Lange | 11 |
| Centaurea corymbosa Pourr. | 3 |
| Centaurea gadorensis Blanca | 3 |
| Centaurea gymnocarpa Moris & De Not. | 1 |
| Centaurea haenseleri (Boiss.) Boiss. | 2 |
| Centaurea kunkelii GarcÃa-Jacas | 3 |
| Centaurea lactucifolia Boiss. | 1 |
| Centaurea lainzii Fern.Casas | 4 |
| Centaurea lancifolia Sieber ex Sprengel | 1 |
| Centaurea monticola Boiss. ex DC. | 4 |
| Centaurea musarum Boiss. & Orph. | 2 |
| Centaurea paniculata L. subsp. esterellensis (Burnat ex Briq.) Dostál | 1 |
| Centaurea peucedanifolia Boiss. & Orph. | 1 |
| Centaurea pinnata Pau | 3 |
| Centaurea poculatoris Greuter | 7 |
| Centaurea pulvinata (Blanca) Blanca | 2 |
| Centaurea sagredoi Blanca | 1 |
| Centaurea saxicola Lag. | 6 |
| Centaurea tauromenitana Guss. | 2 |
| Centaurea ucriae Lacaita s.l. | 1 |
| Centaurea ultreiae Silva Pando | 1 |
| Cephalanthera cucullata Boiss. & Heldr. | 7 |
| Cerastium nigrescens (H.C.Watson) H.C.Watson | 2 |
| Cerastium soleirolii Duby | 2 |
| Cerastium theophrasti Merxm. & Strid | 3 |
| Ceratocapnos claviculata (L.) Lidén subsp. picta (Samp.) Lidén | 1 |
| Chaerophyllum creticum Boiss. & Heldr. | 1 |
| Cheirolophus lagunae Olivares Peris Stiibing & MartÃn | 4 |
| Cheirolophus mansanetianus G.Stübing J.B.Peris A.Olivares & J.MartÃn | 6 |
| Cirsium carniolicum Scop. subsp. rufescens (Raymond ex DC.) P.Fourn. | 2 |
| Cirsium rosulatum Talavera & Valdés | 11 |
| Cistus albanicus E.F. Warb. ex Heywood | 3 |
| Cistus heterophyllus Desf. subsp. carthaginensis (Pau) M.B.Crespo & Mateo | 4 |
| Clematis elisabethae-carolae Greuter | 1 |
| Clypeola eriocarpa Cav. | 2 |
| Cochlearia polonica Fröhlich | 5 |
| Coincya longirostra (Boiss.) Greuter & Burdet | 50 |
| Coincya monensis (L.) Greuter & Burdet subsp. puberula (Pau) Leadley | 1 |
| Coincya nivalis (Boiss. & Heldr.) Greuter & Burdet | 2 |
| Coincya rupestris Porta & Rigo ex Rouy | 12 |
| Coincya rupestris Porta & Rigo ex Rouy subsp. leptocarpa (Gonz.Albo) Leadlay | 14 |
| Coincya wrightii (O.E.Schulz) Stace | 8 |
| Colchicum cousturieri Greuter | 1 |
| Coleanthus subtilis (Tratt.) Seidel ex Roem. & Schult. | 11 |
| Convolvulus argyrothamnos Greuter | 5 |
| Convolvulus valentinus Cav. | 4 |
| Coronopus navasii Pau | 8 |
| Crepis auriculifolia Sieber ex Sprengel | 7 |
| Crepis bivoniana (Reichenb.) Soldano & F. Conti | 1 |
| Crepis granatensis (Willk.) Blanca & Cueto | 6 |
| Crepis pusilla (Somier) Merxm. | 2 |
| Crepis sibthorpiana Boiss. & Heldr. | 4 |
| Crocus cyprius Boiss. & Kotschy | 5 |
| Crocus etruscus Parl. | 3 |
| Crocus hartmannianus Holmboe | 3 |
| Crocus siculus Tineo | 1 |
| Cymbalaria fragilis (J.J. Rodr.) A. Cheval | 2 |
| Cynoglossum nebrodense Guss. | 2 |
| Cynoglossum sphacioticum Boiss. & Heldr. | 5 |
| Cynoglossum troodi H. Lindb. fil. | 6 |
| Cytisus emeriflorus Rchb. | 4 |
