Abstract: Phacellaria rigidula Benth.(Santalaceae)is one kind of holo-parasitic mini-shrub.It parasites mainly on Taxillus calareas var. fargesii H.S.Kiu(Loranthaceae).It has many specialized morphological and ana tomical features.The plumule degenerated during the mature of the seed.The devel oping radicle penetrated bark of the host plant in which to form parasitic roots ,which differentiated further into cortical and haustorial root entering into va scular system.In fact,the parasitic plant out of the host is root sprout of the remind cortical root.For the plant there is only a very short vegetative section with very small alternate scale-leaves.The most part of the plant belongs to r eproductive section what bears flowers.The fascicled flowers do not have a commu nal rachis,but every flower has a very short pedicel with four little bracts.The flower is unisexual and dioecious with 4 tepals usually.The male one has 4 stam ens whose anthers are respectively of 4 locules.The female one has an inferior o vary made of 1 locule and free central placentation in which there are 4 ovules usually,but only one can develop to a seed.The fruit comprises of pericarp,sarco carp and drupe from outside.There is a layer of gelatinous cells from the carcar p on the drupe and one seed in the drupe.The seed has well developed endosperm w ith a columnar embryo in the central,but has not coat due to lacking of integume ntum.