Danthonia californica Bolander (Poaceae)is a native perennial bunchgrass commonly used in the restoration of prairie ecosystems in the western United States. Plants of this species simultaneously produce both chasmogamous (potentially outcrossed) and cleistogamous (obligately self‐fertilized) seeds. Restoration practitioners almost exclusively use chasmogamous seeds for outplanting, which are predicted to perform better in novel environments due to their greater genetic diversity. Meanwhile, cleistogamous seeds may exhibit greater local adaptation to the conditions in which the maternal plant exists. We performed a common garden experiment at two sites in the Willamette Valley, Oregon, to assess the influence of seed type and source population (eight populations from a latitudinal gradient) on seedling emergence and found no evidence of local adaptation for either seed type. Cleistogamous seeds outperformed chasmogamous seeds, regardless of whether seeds were sourced directly from the common gardens (local seeds) or other populations (nonlocal seeds). Furthermore, average seed weight had a strong positive effect on seedling emergence, despite the fact that chasmogamous seeds had significantly greater mass than cleistogamous seeds. At one common garden, we observed that seeds of both types sourced from north of our planting site performed significantly better than local or southern‐sourced seeds. We also found a significant seed type and distance‐dependent interaction, with cleistogamous seedling emergence peaking approximately 125 km from the garden. These results suggest that cleistogamous seeds should be considered for greater use in D. californica restoration.

Danthonia californica is a native perennial bunchgrass commonly used in the restoration of prairie ecosystems in the western United States. Plants of this species simultaneously produce both chasmogamous (potentially outcrossed) and cleistogamous (obligately self-fertilized) seeds. Restoration practitioners almost exclusively use chasmogamous seeds for outplanting, which are predicted to perform better in novel environments due to their greater genetic diversity. Meanwhile, cleistogamous seeds may exhibit greater local adaptation to the conditions in which the maternal plant exists. We performed a common garden experiment at two sites in the Willamette Valley, Oregon to assess the influence of seed type and source population (eight populations) on germination and found no evidence of local adaptation for either seed type. Cleistogamous seeds outperformed chasmogamous seeds regardless of whether seeds were sourced directly from the common gardens (local seeds), or other populations (nonlocal seeds). Furthermore, average seed weight had a strong positive effect on germination success, despite the fact that chasmogamous seeds had significantly greater mass than cleistogamous seeds. At one common garden we observed that seeds of both types sourced from north of our planting site performed significantly better than local or southern-sourced seeds. We also found a significant seed type and distance-dependent interaction, with cleistogamous germination peaking approximately 125km from the garden, which may be explained by differences in the pathogen content of cleistogamous and chasmogamous seeds. These results suggest that cleistogamous seeds should be considered for greater use in D. californica restoration.

This paper presents an experimental investigation of how English-learning children acquire the additive discourse particles either and too. In the target grammar these items exhibit near-complementary distribution conditioned on the polarity of their host sentence. The path leading to that grammar appears to be rather intricate. We present comprehension data showing that for an extended period of time (3–5 ya) learners find both items acceptable in both polarity environments, exhibiting only a weak adult-like tendency of preferring either in negative and too in positive sentences. At 6 ya, their grammar appears categorical wrt. either in that they no longer tolerate it in positive sentences while still exhibiting only a weak dispreference for too in negative environments. These findings are even more striking in the context of production data. We find that child-directed speech is essentially categorical, providing unambiguous evidence for the adult grammar. Moreover, we find essentially categorical, adult-like use of either and too in child production from the earliest stage of development. These observations raise a number of challenges for theories of either and too and for approaches to learning focus particles more generally. Perhaps most strikingly, the protracted insensitivity of the learner's grammar to accumulation of unambiguous evidence constitutes a novel argument from the abundance of evidence for encapsulated learning.