The chapter by Alwyn H. Gentry, titled "Patterns of Neotropical Plant Species Diversity," explores the central role of diversity in ecological theory and the need for detailed documentation of diversity patterns within the tropics. The author discusses the controversy over how diversity should be measured, favoring species richness over equitability. The species-area curve, which describes the relationship between species number and sample area, is a key concept. Most studies on this relationship have been conducted in temperate zones, but some have examined tropical forests, revealing that tropical plant communities generally have higher species richness and a larger k value compared to temperate counterparts. However, Huston's recent work challenges the positive correlation between plant species diversity and soil fertility, suggesting that rich soils may lead to higher growth rates and competitive displacement. The significance of these findings is questioned due to the relatively rich soils of the Costa Rican sites studied.The chapter by Alwyn H. Gentry, titled "Patterns of Neotropical Plant Species Diversity," explores the central role of diversity in ecological theory and the need for detailed documentation of diversity patterns within the tropics. The author discusses the controversy over how diversity should be measured, favoring species richness over equitability. The species-area curve, which describes the relationship between species number and sample area, is a key concept. Most studies on this relationship have been conducted in temperate zones, but some have examined tropical forests, revealing that tropical plant communities generally have higher species richness and a larger k value compared to temperate counterparts. However, Huston's recent work challenges the positive correlation between plant species diversity and soil fertility, suggesting that rich soils may lead to higher growth rates and competitive displacement. The significance of these findings is questioned due to the relatively rich soils of the Costa Rican sites studied.