You are reading a tafsir for the group of verses 55:64 to 55:69

مُدْهَامَّتَانِ (both dark green!...55:64). This is one word verse, and it means 'dark green with foliage'. The word is derived from idhimam signifying, for a meadow or garden, to become of dark green hue inclining to black by reason of abundance of moisture or irrigation. This description is not assigned to the first two Gardens. This does not necessarily imply that they do not have this quality. The former Gardens are described as ذَوَاتَا of 'having lot of branches'. This comprehends the quality of 'dark green' as well.