无根藤属 (或称为无根草属，Cassytha L.) 为樟科植物的一个属，寄生性的藤本植物。广泛布于热带地区。

无根藤属植物的茎具缠绕性，藉吸器寄生于多种乔木及灌木植株上。植株体内具黏液，绿色或灰褐色，线形，具分枝。

叶退化，细小、呈鳞片状。

花小型，两性 (极少为雌雄异株的单性花，若此情况可能缘于雄不稔或雌不稔之未正常发育)。花具柄或无柄，苞片鳞片状，具两枚小苞片与花被合生。花聚生成穗状、头状、或总状的花序。

花被管呈倒圆锥形或卵形，开花后顶端收缩。花被片6枚，呈2轮，外轮的3枚极小。雄蕊9枚，其中第2轮雄蕊少数状况下会退化为细小的假雄蕊。第1轮及第2轮的花丝不具腺体，第3轮具有无柄的腺体。花药2室，第1轮及第2轮的花药朝内生长，第3轮则为朝外生长。假雄蕊3枚，具柄或无柄。

Cassytha is a genus of some two dozen species of obligately parasitic vines in the family Lauraceae. Superficially, and in some aspects of their ecology, they closely resemble plants in the unrelated genus Cuscuta, the dodders. The physical resemblance is so close, when fruit and flowers are absent in the field, few people without technical training can tell them apart. The two genera present a spectacular example of convergent evolution. In its divergence from habits typical of the Lauraceae, Cassytha also presents examples of mosaic evolution