Sentence:  <WSD>Polyembryony</WSD> was first reported by Leeuwenhoek in citrus as early as 1719 and the different cases of <WSD>polyembryony</WSD> were studied by Braun in 1859. 
Meaning of the word marked with <WSD> tags:  The production of two or more embryos in one seed, due either to the existence and fertilization of more than one embryonic sac or to the origination of embryos outside of the embryonic sac.