Phylogenetics of the Chamaesyce clade (Euphorbia, Euphorbiaceae): Reticulate evolution and long‐distance dispersal in a prominent C4 lineage

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142099/1/ajb21486.pd

Chromosome Number Changes Associated with Speciation in Sedges: a Phylogenetic Study in Carex section Ovales (Cyperaceae) Using AFLP Data

Phylogenetic analysis of amplified fragment length polymorphisms (AFLP) was used to infer patterns of morphologic and chromosomal evolution in an eastern North American group of sedges (ENA clade I of Carex sect. Ovales). Distance analyses of AFLP data recover a tree that is topologically congruent with previous phylogenetic estimates based on nuclear ribosomal DNA (nrDNA) sequences and provide support for four species groups within ENA clade I. A maximum likelihood method designed for analysis of restriction site data is used to evaluate the strength of support for alternative topologies. While there is little support for the precise placement of the root, the likelihood of topologies in which any of the four clades identified within the ENA clade I is forced to be paraphyletic is much lower than the likelihood of the optimal tree. Chromosome counts for a sampling of species from throughout sect. Ovales are mapped onto the tree, as well as counts for all species in ENA clade I. Parsimony reconstruction of ancestral character states suggest that: (1) Heilborn’s hypothesis that more highly derived species in Carex have higher chromosome counts does not apply within sect. Ovales, (2) the migration to eastern North America involved a decrease in average chromosome count within sect. Ovales, and (3) intermediate chromosome counts are ancestral within ENA clade I. A more precise understanding of chromosomal evolution in Carex should be possible using likelihood analyses that take into account the intraspecific polymorphism and wide range of chromosome counts that characterize the genus

(2011) Proposal to conserve the name Euphorbia acuta Engelm. against E. acuta Bellardi ex Colla (Euphorbiaceae)

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146931/1/tax602042.pd

William Russell Anderson (1942–2013)

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147021/1/tax63114.pd

Can billiard eigenstates be approximated by superpositions of plane waves?

The plane wave decomposition method (PWDM) is one of the most popular strategies for numerical solution of the quantum billiard problem. The method is based on the assumption that each eigenstate in a billiard can be approximated by a superposition of plane waves at a given energy. By the classical results on the theory of differential operators this can indeed be justified for billiards in convex domains. On the contrary, in the present work we demonstrate that eigenstates of non-convex billiards, in general, cannot be approximated by any solution of the Helmholtz equation regular everywhere in $\R^2$ (in particular, by linear combinations of a finite number of plane waves having the same energy). From this we infer that PWDM cannot be applied to billiards in non-convex domains. Furthermore, it follows from our results that unlike the properties of integrable billiards, where each eigenstate can be extended into the billiard exterior as a regular solution of the Helmholtz equation, the eigenstates of non-convex billiards, in general, do not admit such an extension.Comment: 23 pages, 5 figure

Nomenclature and taxonomy of Croton glabellus L. (Euphorbiaceae), a widespread Caribbean species

The application of the names Croton glabellus, C. lucidus, and Phyllanthus glabellus has been confusing since the earliest publications that used them. After a thorough review of these publications and corresponding herbarium specimens, we clarify the nomenclatural confusion surrounding these names and their taxonomy. We identify a new name, Phyllanthus glabellus Fawc. & Rendle, that was inadvertently made. We make the new combination Croton glabellus subsp. polytrichus, and we designate lectotypes for Astrocasia tremula, Croton subsect. Astraeopsis, C. glandulifer, C. lucidus var. polytrichus, and C. spicatus.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146901/1/tax605029.pd

A revised infrageneric classification and molecular phylogeny of New World Croton (Euphorbiaceae)

Croton (Euphorbiaceae) is a large and diverse group of plants that is most species‐rich in the tropics. We update the infrageneric classification of the New World species of Croton with new evidence from phylogenetic analyses of DNA sequence data from all three genomes. The relationships of species that were previously placed in conflicting positions by nuclear and chloroplast data, such as C. cupreatus, C. poecilanthus, and C. setiger, are further resolved by adding the nuclear EMB2765 and mitochondrial rps3 genes to the molecular sampling. Analyses of rps3 reveal an accelerated rate of evolution within Croton subg. Geiseleria, the only one of the four subgenera that contains numerous herbaceous, annual species. We provide morphological descriptions, species lists, and a key to the 31 sections and 10 subsections recognized in the New World. New taxa that we describe include C. sects. Alabamenses, Argyranthemi, Cordiifolii, Corinthii, Cupreati, Luetzelburgiorum, Nubigeni, Olivacei, Pachypodi, Prisci, and C. subsects. Cubenses, Jamaicenses, and Sellowiorum. Additional transfers are made to the ranks of subgenus, section, and subsection. A total of 712 species of Croton are currently recognized for the New World, with 702 of them assigned here to section.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146834/1/tax603013.pd

Promoting Prosocial Responsiveness across Racial Divides through Mindfulness

In interracial and other intergroup interactions, prosocial emotions and actions are often undermined (Cikara & van Bavel, 2014). Perceiving psychological separateness between “us” and “them” – which is often an automatic, unintentional process – is psychological kindling for lower prosocial responsiveness that leads to prejudice, discrimination, aggressive conflict (Cikara, 2015). Recent research has shown that mindfulness, an open and unconditional attention to one’s present experiences, is associated with decreased automaticity and racial bias (Kang, Gruber, & Gray, 2013; Lueke & Gibson, 2014), barriers that hinder prosocial responsiveness (Trautwien, Schmidt, & Naranjo, 2014). Two experiments investigated whether brief mindfulness training promoted prosocial responsiveness toward an ostracized person of another race. Before witnessing a person of another race being excluded in an online ball-tossing game (Cyberball), participants in both studies were randomized to either an audio-recorded mindfulness training (MT), a structurally-equivalent attention control training (CT), or a no instruction control (NT). MI participants in Study 1 (N=124) showed trends towards higher empathic concern (p=.065), while MI participants in Study 2 (N=131) reported higher empathic concern for the excluded player (p\u3c0.05). MI participants in both studies wrote more comforting emails to them (p\u3c0.01), as coded for prosociality (c.f., Masten et al., 2011). Only in Study 2 did MI participants passed the ball more to the victim in an ‘all play’ game (p\u3c.05), presumably because their identity was less “known” than in Study 1; specifically, players’ photo images were loaded into the game in Study 1, but only first names were shared in Study 2. These studies underscore the potential for mindfulness training to foster sensitive attitudes across social and cultural lines within increasingly growing anonymous (i.e., online) contexts.https://scholarscompass.vcu.edu/uresposters/1222/thumbnail.jp

Phylogeny, Adaptive Radiation, and Historical Biogeography of Bromeliaceae Inferred from ndhF Sequence Data

Cladistic analysis of ndhF sequences identifies eight major bromeliad clades arranged in ladderlike fashion. The traditional subfamilies Tillandsioideae and Bromelioideae are monophyletic, but Pitcairnioideae are paraphyletic, requiring the description of four new subfamilies, recircumscription of Pitcairnioideae and Navioideae, the sinking of Ayensua, and description of the new genus Sequencia. Brocchinioideae are basalmost, followed by Lindmanioideae, both restricted to the Guayana Shield. Next is an unresolved trichotomy involving Hechtioideae from Central America, Tillandsioideae, and the remaining bromeliads in subfamilies Navioideae, Pitcairnioideae, Puyoideae, and Bromelioideae. Bromeliads arose as C3 terrestrial plants on moist infertile sites in the Guayana Shield roughly 70 Mya, spread centripetally in the New World, and reached tropical West Africa (Pitcairnia feliciana) via long-distance dispersal about 10 Mya. Modern lineages began to diverge from each other 19 Mya and invaded drier areas in Central and South America beginning 15 Mya, coincident with a major adaptive radiation involving the repeated evolution of epiphytism, CAM photosynthesis, impounding leaves, several features of leaf/trichome anatomy, and accelerated diversification at the generic level. This ‘‘bromeliad revolution’’ occurred after the uplift of the northern Andes and shift of the Amazon to its present course. Epiphytism may have accelerated speciation by increasing ability to colonize along the length of the Andes, while favoring the occupation of a cloud-forest landscape frequently dissected by drier valleys. Avian pollination (mainly by hummingbirds) evolved at least twice ca. 13 Mya; entomophily was ancestral. Hechtia, Abromeitiella–Deuterocohnia–Dyckia–Encholirium, and Puya exhibit a remarkable pattern of concerted convergence in six anatomical and physiological leaf traits adapted to drought

Dos nuevas especies suramericanas de Croton (Euphorbiaceae) y sus afinidades filogenéticas

Two rarely collected species of Croton from South America are des cribed and illustrated. Croton chimboracensis P.E. Berry & Riina is localized in western Andean Ecuador and is sister to Croton sect. Adenophyllum Griseb. Croton abonari Riina & P.E. Berry is known from a single location in Amazonian Brazil; it resembles both C. sampatik Müll. Arg. and members of Croton sect. Cuneati (G.L. Webster) Riina & P.E. Berry, but C. abonari can be easily distinguished from both groups by distinctive morphological charactersSe describen e ilustran dos especies raras de Croton de Suramérica. Croton chimboracensis P.E. Berry & Riina está localizada en los Andes occidentales de Ecuador y es hermana del clado de Croton sect. Adenophyllum Griseb. Croton abonari Riina & P.E. Berry se conoce de una sola localidad en la Amazonia de Brasil; es similar tanto a C. sampatik Müll. Arg. y a miembros de la sección Cuneati (G.L. Webster) Riina & P.E. Berry, pero C. abonari se puede diferenciar de ambos grupos por varios caracteres morfológicos distintivos