THE FOLIAGE IS THE FRUIT HYPOTHESIS - COMPLEX ADAPTATIONS IN BUFFALOGRASS (BUCHLOE DACTYLOIDES)

Buffalograss (Buchloe dactyloides) has been described as an excellent fir for Janzen's ''Foliage is the Fruit'' (FF) hypothesis, which sugge sts that large grazing animals ingest and later disperse seeds of some herbs when consuming their foliage. We tested this hypothesis by feed ing buffalograss burs and legume seeds to ruminally fistulated beef st eers. Our objectives were to determine (1) rumen residence times of bu ffalograss burs, free buffalograss caryopses and legume seeds; (2) tot al tract residence times for the three types of propagules; (3) percen tage propagule survival after passage and (4) germinability of fed and unfed burs and caryopses. Bur survival (3%) and germination percentag e were lower than previously reported, but this can be explained by di fferences in feeding and germination procedures. Significant numbers o f free caryopses recovered from the feces also germinated. Previously undescribed hairs on the burs' awn-like projections delayed passage th rough the animals and assured that many burs were broken during rumina tion. We concur that buffalograss is an excellent fit for the FF hypot hesis, but our results and observations suggest that the buffalograss/ grazing-animal interaction is more complex than it initially appeared.