Cushions of Thylacospermum caespitosum (Caryophyllaceae) do not facilitate other plants under extreme altitude and dry conditions in the north-west Himalayas.

Background: Cushion plants are commonly considered as keystone nurse species that ameliorate the harsh conditions they inhabit in alpine ecosystems, thus facilitating other species and increasing alpine plant biodiversity. A literature search resulted in 25 key studies showing overwhelming facilitative effects of different cushion plants and hypothesizing greater facilitation with increased environmental severity (i.e.

Supernetwork identifies multiple events of plastid trnF(GAA) pseudogene evolution in the Brassicaceae.

The occurrence of nonfunctional trnF pseudogenes has been rarely described in flowering plants. However, we describe the first large-scale supernetwork for the Brassiccaeae built from gene trees for 5 loci (adh, chs, matK, trnL-F, and ITS) and report multiple independent origins for trnF pseudogenes in crucifers. The duplicated regions of the original trnF gene are comprised of its anticodon domain and several other highly structured motifs not related to the original gene.