boughs or bouquets of flowers held in the hands
Macxochitl seems to be a variant spelling; see the Florentine Codex, Book 11, folio 198v., which has several examples.
The Matrícula de Huexotzinco of 1560 includes Nahuatl hieroglyphs for several people who held the name Maxochitl. Searching the word maxochitl will bring up several examples which seem to show hand-held flower bouquets.
opeuhqui y maçehualtin ynic ye mocueçohua inic opeuh yca xochitopili ynic mochi maxochitl = empezaron a enojarse los macehuales; empezaron por las varas de flores [xochitopilli] y todos los ramilletes de flores para las manos [maxochitl] (Tlaxcala, 1662–1692)