Discovering Polycnemoideae - an old, rare, strangely distributed and largely unknown subfamily of the Amaranthaceae/Chenopodiaceae alliance

分子生物学研究表明，苋科/藜科（Amaranthaceae/Chenopodiaceae alliance，A/C alliance）由三个主要的谱系组成，主要分布于热带的苋科（Amaranthaceae）s.str.（c. 1000种），主要分布于亚热带和暖温带，通常喜盐的藜科（约100年）。1230 spp.）和Polycnemoideae（16种）。虽然这两个物种丰富的谱系藜科和苋科已经或目前正在详细研究，很少有人知道的物种贫乏Polycnemoideae。为了了解A/C联盟的演变，有必要更多地了解这个小亚科的生殖、生态和地理。Polycnemoideae起源于始新世早期，由三个小的，间断分布的属组成，Polycnemum（6种;欧亚大陆）、半边莲属（Hemichroa）（3种，澳大利亚）和嗜氮菌属（Nitrophila）（7种;产于美洲的两性花（amphitrophilus）是一种不显眼的草本植物，生长在各种开放的栖息地，包括杂草或盐碱地和农田。该项目使用过时的分子生物学和详细调查的形态和分布的所有c。16个物种发现1.他们的祖先范围，栖息地的喜好和形态和2。它们的形态、生态和地理多样化模式。我想弄清楚Polycnemoideae是否代表了一个古老的多样化或一个古老谱系的年轻多样化的残余，并追踪其主要的大陆间和大陆内传播事件的顺序。

Molecular studies have shown that the Amaranthaceae/Chenopodiaceae alliance (A/C alliance) consist of three major lineages, the predominantly tropical Amaranthaceae s.str. (c. 1000 spp.), the largely subtropical and warm-temperate, often halophilous Chenopodiaceae (c. 1230 spp.) and the Polycnemoideae (16 spp.). While the two speciesrich lineages Chenopodiaceae and Amaranthaceae have been or are currently studied in detail, little is known about the species-poor Polycnemoideae. To understand the evolution of the A/C alliance it is essential to learn more about the phylogeny, ecology and biogeography of this small subfamily. Polycnemoideae originated during the early Eocene and consist of three small, disjunctly distributed genera, Polycnemum (6 spp.; Eurasia), Hemichroa (3 spp., Australia) and Nitrophila (7 spp.; amphitropical in America) that are inconspicuous herbs growing in various open habitats including ruderal or saline sites and agricultural land. This project uses dated molecular phylogenies and detailed surveys of the morphology and distribution of all c. 16 species to discover 1. their ancestral range, habitat preferences and morphology and 2. their modes of morphological, ecological and biogeographical diversification. I would like to find out whether Polycnemoideae represent relicts of an old diversification or a young diversification of an old lineage, and trace the sequence of their major inter- and intracontinental dispersal events.