Monadelpha (Euphorbiaceae, Plukenetieae), a new genus of Tragiinae from the Amazon rainforest of Venezuela and Brazil

Monadelpha L.J.Gillespie & Card.-McTeag., gen. nov., is described as a new member of Euphorbiaceae tribe Plukenetieae subtribe Tragiinae, to accommodate Tragia guayanensis, a species known from western Amazonas, Venezuela and, newly reported here, from Amazonas, Brazil. The genus is unique in the subtribe for having 5-colpate pollen and staminate flowers with filaments entirely connate into an elongate, cylindrical staminal column terminated by a tight cluster of anthers. Phylogenetic analyses based on nuclear rDNA ITS and sampling 156 accessions across the diversity of Tragiinae (all 12 genera and 77 of ~195 species) also support Monadelpha as a distinct lineage that is separate from Tragia. A revised key to the genera of Tragiinae in South America and Central America is provided.

A new outstanding species and a new section of Dalea (Fabaceae: Papilionoideae) from central Mexico

We describe and illustrate Dalea rubriflora A.E. Estrada, J. Martínez-Ramírez, A. Mares & Ocampo as a new species from central Mexico. According to the morphology of its flower, this new species is included in a new section within subgenus Parosela because the shape of its keel, the innermost petals (which make the flower valvate) coherent along their external (dorsal) outer margins. However, this new species and new section have striking differences with the rest of the previously described taxa of subgenus Parosela, highlighting 1) the persistent red color of the flowers, not found in any section and species of Dalea, 2) the stamens are joined in a very long staminal column which are protruded from the keel petals for almost a third of its length, and 3) the blades of the epistemonous petals are not auriculated, instead, are truncated in the keel and absent in the wings. These main features, associated with more particular characteristics of other sections, allow us to recognize Rubriflorae as a new section and Dalea rubriflora as a new species into the subgenus Parosela.

Virola dominicana sp. nov. (Myristicaceae) from Dominican amber

The Myristicaceae is a member of the early diverging angiosperm order Magnoliales; however, the family is poorly represented by fossil collections. We describe Virola dominicana sp. nov. (Myristicaceae), the first record of fossilized Myristicaceae flowers, from mid-Tertiary (45–15 million years ago) Dominican amber. The description is based on 24 male flowers in 17 pieces of amber, thus providing some indication of intraspecific variation, including a two-tepaled flower. Diagnostic characters of the new species are the long-simple or few-branched trichomes on the perianth margins, the small pollen grains, and a short staminal column. These fossils also show co-occurring insects, some of which could be Virola pollinators. It is speculated that V. dominicana disappeared from Hispaniola during the Pliocene–Pleistocene cooling events leaving no native members of the Myristicaceae in this region today. Additionally, these fossils demonstrate that Myristicaceae was present in the Western Hemisphere during the mid-Tertiary.

Glufosinate Does Not Affect Floral Morphology and Pollen Viability in Glufosinate-Resistant Cotton

Studies were conducted to determine whether glufosinate treatments to glufosinate-resistant cotton caused changes in floral morphology, pollen viability, and seed set. Four glufosinate treatments were included: (1) glufosinate applied postemergence over the top (POST) at the four-leaf stage, (2) glufosinate applied POST at the eight-leaf stage, (3) the first two treatments sequentially, and (4) a POST application at the four-leaf stage followed by (fb) a postemergence-directed stem application (PDS) at the eight-leaf stage. Glufosinate was consistently applied at 0.49 kg ai/ha. A nontreated control was included. Glufosinate treatments did not affect stigma height, length of the staminal column, or pollen viability. However, the distance from the top anther to the tip of the stigma was less in plants treated with an eight-leaf POST treatment than in nontreated plants, although this difference is not likely to influence pollen deposition because in both cases anthers reached above the stigma tip. Plants receiving four-leaf POST fb eight-leaf PDS treatment with glufosinate had eight seeds per boll less than nontreated plants; however, the more rigorous four-leaf POST fb eight-leaf POST treatment did not differ from the nontreated in seeds per boll.

A SINGLE FACTOR MUTATION IN MELILOTUS ALBA DESC. HAVING MULTIPLE EFFECTS ON HOMOLOGOUS STRUCTURES

The multiple effect of a single factor mutation in Melilotus alba which affects several diverse characters of the plant including shape of leaflets and petals, position of the staminal column, morphology of the pistil, female fertility and vigor of growth, is described.The results are significant in showing that one of the genes which presumably determined leaf shape in the species ancestor still continues to modify the shape of those organs which have evolved from the leaf.