Floral fragrances play an important role in pollinator attraction; they serve as signals for primary rewards such as nectar. The presence of osmophores (a specialized glandular tissue that produces fragrance) in the terrestrial orchid Cyclopogon has only been described in a single species. There are fragrant and odorless species within this genus, but no data on the similarities or differences between them has been published. Here, we present new data on the lip morphology and ultrastructure from eight Cyclopogon species to better understand the mechanisms of pollinator attraction of this group. To achieve this goal, we used light, scanning, and transmission electron microscopy. Five out of eight species presented globular trichomes associated with fragrance production on the abaxial side of the labellum. Together with subepidermal cells, they compose the secretory tissue. Despite the absence of globular trichomes, C. apricus also presented cells associated with fragrance production. Lipid droplets, plastids containing plastoglobuli, and starch were indicators of secretory activity present in these species. This same pattern of fragrance production and release, associated with flower morphology, may result in the restriction of pollination by halictid bees.

中文翻译：

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Cyclopogon (Orchidaceae) 中渗透压的唇形和超微结构揭示了物种间的一定程度的形态分化

花香在吸引传粉媒介方面发挥着重要作用；它们作为主要奖励（如花蜜）的信号。陆生兰花 Cyclopogon 中渗透压物质（一种产生香味的特殊腺体组织）的存在仅在一个物种中被描述过。该属中存在有香味和无味的物种，但尚未发表关于它们之间异同的数据。在这里，我们提供了有关八种 Cyclopogon 物种的唇部形态和超微结构的新数据，以更好地了解该组传粉媒介吸引力的机制。为了实现这一目标，我们使用了光学、扫描和透射电子显微镜。八分之五的物种在唇瓣的背面呈现与香味产生相关的球状毛状体。与表皮下细胞一起，它们构成分泌组织。尽管没有球状毛状体，C. apricus 也存在与香味产生相关的细胞。脂滴、含有质体球蛋白的质体和淀粉是这些物种中分泌活动的指标。这种与花朵形态相关的香味产生和释放的相同模式可能会导致比蜂类蜜蜂授粉受到限制。