A New and Expanded Phylogenetic Analysis of Hyptidinae (Ocimeae-Lamiaceae)

Abstract— Hyptidinae, ca. 400 species, is an important component of Neotropical vegetation formations. Members of the subtribe possess flowers arranged in variously modified bracteolate cymes and nutlets with an expanded areole and all share a unique explosive mechanism of pollen release, except for Asterohyptis. In a recent phylogenetic study, the group had its generic delimitations rearranged with the recognition of 19 genera in the subtribe. Although the previous phylogenetic analysis covered almost all the higher taxa in the subtribe, it lacked a broader sampling at the species level. Here we present a new expanded phylogenetic analysis for the subtribe comprising 153 accessions of Hyptidinae sequenced for the nuclear nrITS, nrETS, and waxy regions and the plastid markers trnL-F, trnS-G, trnD-T, and matK. Our results widely support the previous phylogenetic results with some changes in the support and relationship between genera. It also uncovers the need for a new combination of Eriope machrisae in Hypenia and the phylogenetic position of Hyptis sect. Rhytidea, which was demonstrated to be part of Mesosphaerum. The generic delimitation in Hyptidinae is discussed, and we recommend that further studies with more markers are needed to confirm the monophyly of Hyptidendron and Mesosphaerum, as well as to support taxonomic changes on the infrageneric delimitation within Hyptis s. s.

Reproductive biology of four weedy Euphorbia species from Ile-Ife, Nigeria

Euphorbia heterophylla Linn., Euphorbia hirta Linn., Euphorbia hyssopifolia Linn. and Euphorbia prostrata Linn. are four noxious, yet economically important weeds, useful as phytomedicine in some parts of the world and also in Nigeria. Studies were carried out on their reproductive biology with a view to understanding the mode of their spread. Parameters investigated include number of days to seedling emergence, germinationpercentage, number of days to flowering, period to anthesis, pollinators, pollen viability, pollen size, floral structure, fruits type, seeds type, average number of fruit per plant, average number of seeds per plant and mode of seed dispersal. Results obtained showed that the seedlings of the four Euphorbia species studied emerged within 3 to 5 days; numbers of days to 50% flowering took 44 to 58 days; while flowering and fruiting continuedthroughout the remaining part of the year; thus exhibited r-strategy, expending more time and allocation of resources on their reproductive phases than their vegetative phases. Also differences existed in their stigma shape, perianth colour, perianth texture, pollen sizes, pollen viability as well as ripened colour of seed which were all significant characters that could be useful in delimiting the species. Furthermore, the study revealed that thefour species were essentially insect pollinated and their seeds dispersed by means of explosive mechanism usually characteristic of their schizocarpic fruits. This ability as well as their tendency to exhibit r-strategy could probably account for their ability to spread and invade cultivated fields, waste lands and roadsides. Keywords: Explosive mechanism, r-Strategy, Seed dispersal, Pollen viability, Seed set

Experimental and Theoretical Aspects Regarding Design and Testing of Thermobaric Munitions for Recoilless Armament Systems

The purpose of this paper is to present theoretical and experimental aspects regarding the design and testing of a thermobaric unguided fin-stabilized reactive projectile destined to be fired from a recoilless smoothbore gun, namely the anti-tank grenade launcher SPG-9 (AG-9). Some theoretical aspects regarding thermobaric explosive mechanism are presented and experimental determinations are made considering the relation between the explosive core and the overall calibre of the munition. The interior and exterior ballistics of the munitions are estimated by mathematical models and the results are validated through experimental firings with the prototype munition. The destructive effect of the munition is estimated by real firings against buildings and structures