( This ( ( ( produces ( new plants ) ) ( by ( ( ( vegetative propagation ) , ) ( ( a form ) ( of ( asexual reproduction ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ produces) (NP (JJ new) (NNS plants)) (PP (IN by) (NP (NP (JJ vegetative) (NN propagation)) (, ,) (NP (NP (DT a) (NN form)) (PP (IN of) (NP (JJ asexual) (NN reproduction))))))) (. .)))
This produces new plants by vegetative propagation, a form of asexual reproduction.
(ROOT (S (NP (NNP Trees)) (VP (VBP send) (PRT (RP out)) (NP (NP (JJ rootlike) (NNS extensions)) (SBAR (WHNP (WDT that)) (S (VP (VBP produce) (SBAR (S (NP (JJ new) (NNS stems)) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (JJ asexual) (NN reproduction)))))))))))) (. .)))
Trees send out rootlike extensions that produce new stems is an example of asexual reproduction.