These features refer to the tenth leaf stage. The tenth leaf is the tenth true leaf produced after the cotyledons. On seedlings with alternate or spirally arranged leaves it is just simply the tenth leaf produced. On seedlings with opposite leaves it is one of the leaves in the fifth pair of true leaves produced. On seedlings with whorled leaves it will be one of the leaves in the appropriate whorl; e.g. if there are four leaves in each whorl then the tenth leaf will be one of the leaves in the third whorl.
Pulvini are fleshy swellings on the petiole at its junction with the leaf blade. They are often associated with an angle or change of direction of the petiole. Swellings at the junction of the petiole and the stem are not regarded as pulvini. In the case of compound leaves, swellings at the junction of the leaflet stalk and leaflet blade are regarded as pulvini.