The grass family Poaceae is the largest group of flowering plants present on the island of Puerto Rico. With 258 species, it represents 9% of all Angiosperms and 33% of all Monocots.
The following is a list of grass species known to exist in Puerto Rico, separated by genus:
- Diectomis fastigiata
- Diectomis argillacea
- Diectomis bicornis
- Diectomis ciliaris
- Diectomis dolichophylla
- Diectomis eriantha
- Diectomis horizontalis
- Diectomis insularis
- Diectomis ischaemum
- Diectomis longiflora
- Diectomis nuda
- Diectomis panicea
- Diectomis sanguinalis
- Diectomis setigera
- Diectomis similis
- Diectomis villosa
- Diectomis violascens
- Paspalum arundinaceum
- Paspalum bakeri
- Paspalum blodgettii
- Paspalum boscianum
- Paspalum caespitosum
- Paspalum clavuliferum
- Paspalum conjugatum
- Paspalum convexum
- Paspalum decumbens
- Paspalum densum
- Paspalum dilatatum
- Paspalum dispar
- Paspalum distichum
- Paspalum fasciculatum
- Paspalum fimbriatum
- Paspalum laxum
- Paspalum macrophyllum
- Paspalum maritimum
- Paspalum millegrana
- Paspalum minus
- Paspalum molle
- Paspalum notatum
- Paspalum orbiculatum
- Paspalum paniculatum
- Paspalum parviflorum
- Paspalum paucispicatum
- Paspalum pleostachyum
- Paspalum plicatulum
- Paspalum pulchellum
- Paspalum rupestre
- Paspalum secans
- Paspalum setaceum
- Paspalum urvillei
- Paspalum vaginatum
- Paspalum virgatum
- Setaria barbata
- Setaria chapmanii, syn. Paspalidium chapmanii
- Setaria geminata, syn. Paspalidium geminatum
- Setaria magna
- Setaria parviflora
- Setaria pradana
- Setaria rariflora
- Setaria setosa
- Setaria tenacissima
- Setaria utowanaea
- Setaria vulpiseta