The inhabitants of the mushroom kingdom, widely known as Toads, are indeed monosexed. They all have the same sexual characteristics and reproduce asexually, like fungi. This does not mean they are monogendered, they may have been at one point, but perhaps by the influence of other creatures have developed a concept of gender, as demonstrated by several toads who take on human genders, such as:
Toadette, who takes on a female gender. And uses she/her pronouns. And
Toadsworth, who takes on a male gender and uses he/him pronouns.
Most toads are genderless and are often confused for male.
Possibly because in English they use male pronouns as the default. It is currently unknown if Toads have their own language and what they use for pronouns, or if they have adopted pronouns for adopted and new genders.
It is indeed possible for toads to take on completely different genders than humans take, including genders exclusive to Mushroom society.
To contrast, consider the Dwarfs of Discworld, who are polysexed and reproduce sexually, however are monogendered and apparently lack secondary sex characteristics that would help them differentiate. Indeed, they all use he/him pronouns and traditional male monikers such as King and foreman. More research is necessary to ascertain how this relates to their own language and it’s attitude towards gender.
In short, Toads are monosexed, but polygendered, however, often genderles. Whereas Discworld dwarfs are polysexed, but monogendered.
ETA (Apr 2016): This Article implies a distinction between sex and gender that the author now understands is a harmful concept since, at least in humans, sex and gender are social constructs that denote the same thing.
