Texas Vascular Plant Checklist:  Rubiaceae
The Madder Family
(Magnoliophyta, Magnoliopsida, Asteridae)

 Asperula
   arvensis L. (woodruff)

 Bouvardia
   ternifolia (Cav.) Schlecht. (scarlet bourvardia, trumpetilla, calvillo)

 Cephalanthus
   occidentalis L. (common buttonbush, honey-balls, globe-flowers)
   salicifolius Humb. & Bonpl. (mexican buttonbush)

 Chiococca
   alba (L.) A.S. Hitchc. (david's milkberry, snowberry, perlilla, canica)

 Cruciata
   pedemontana (Bellardi) Ehrend. (piedmont bedstraw)

 Diodia
   teres var. teres (rough buttonweed, poor-joe)
   virginiana var. latifolia Torr. & Gray
   virginiana var. virginiana (virginia buttonbush, large buttonbush)

 Galium
   aparine L. (catchweed bedstraw, goosegrass cleavers)
   boreale L. (northern bedstraw)
   circaezans var. circaezans
   circaezans var. hypomalacum Fernald
   correllii Dempster (cliff bedstraw)
   fendleri Gray (fendler's bedstraw)
   hispidulum Michx. (coastal bedstraw)
   mexicanum subsp. flexicum Dempster (mexican bedstraw)
   mexicanum subsp. mexicanum
   microphyllum Gray (bracted bedstraw)
   obtusum subsp. obtusum (bluntleaf bedstraw)
   orizabense subsp. laevicaule (Weatherby & Blake) Dempster
   pilosum var. pilosum
   pilosum var. puncticulosum (Michx.) Torr. & Gray
   proliferum Gray (spreading bedstraw)
   texense Gray (texas bedstraw)
   tinctorium (L.) Scop. (dye bedstraw)
   trifidum subsp. subbiflorum (Wieg.) Piper
   triflorum Michx. (fragrant bedstraw, sweet-scented bedstraw)
   uncinulatum DC. (bristly bedstraw)
   uniflorum Michx. (smooth bedstraw)
   virgatum Nutt. (southwest bedstraw)
   wrightii Gray (rothrock bedstraw, wright bedstraw)

 Hedyotis
   angulata Fosberg ex Shinners (small flower star violet)
   butterwickiae (Terrell) Nesom (butterwick's star violet)
   intricata Fosberg (tangle bluets)
   mullerae Fosberg (muller's star violet)
   nigricans var. austrotexana B.L. Turner
   nigricans var. nigricans (prairie bluets)
   nigricans var. papillacea B.L. Turner
   pooleana B.L. Turner (poole's star violet)

 Houstonia
   acerosa (Gray) Gray ex Benth. & Hook. f. (needle leaf bluet)
   correllii (W.H. Lewis) Terrell (correll's bluet)
   croftiae Britton & Rusby (croft's bluet)
   humifusa (Gray) Gray (matted bluet)
   micrantha (Shinners) Terrell (southern bluet)
   parviflora Holz. ex Greenm. (greenman's bluet)
   purpurea var. purpurea
   pusilla Schoepf (tiny bluet)
   rosea (Raf.) Terrell (rose bluet)
   rubra Cav. (red bluet)
   subviscosa (C. Wright ex Gray) Gray (nodding bluet)
   wrightii Gray (pygmy bluet)

 Mitchella
   repens L. (partridge-berry, two-eyed berry, running-box)

 Mitracarpus
   breviflorus Gray (white girdlepod)
   hirtus (L.) DC. (tropical girdlepod)

 Oldenlandia
   boscii (DC.) Chapman (bosc's mille graines)
   corymbosa L. (flat top mille graines)
   uniflora L. (clustered mille graines)

 Paederia
   foetida L. (chinese fevervine)

 Pentodon
   pentandrus (K. Schum.) Vatke (hale's pentodon)

 Randia
   rhagocarpa Standl. (crucillo)

 Richardia
   brasiliensis Gomes (tropical mexicana-clover)
   scabra L. (rough mexican-clover)
   tricocca (Torr. & Gray) Standl. (prairie buttonweed)

 Sherardia
   arvensis L. (spurwort, herb sherard, field-madder)

 Spermacoce
   floridana Urban (florida false buttonweed)
   glabra Michx. (smooth bottonweed)
   tenuior L. (slender bottonweed)
   verticillata L. (shrubby bottonweed, boton blanco)