The Collaborative International Dictionary of English v.0.48:
Flowerless \Flow"er*less\, a. Having no flowers. [1913 Webster] Flowerless plants, plants which have no true flowers, and produce no seeds; cryptogamous plants. [1913 Webster]WordNet (r) 3.0 (2006):
flowerless adj 1: without flower or bloom and not producing seeds; "a flowerless plant" [syn: flowerless, nonflowering] [ant: flowering]