Complex Transitions Between C3 and C4 Photosynthesis During the Evolution of Paniceae: A Phylogenetic Case Study Emphasizing the Position of Steinchisma Hians (Poaceae), A C3-C4 Intermediate

A two-tiered, nested molecular phylogenetic study of panicoid grasses to explore character state transitions between the C3 and C4 adaptive syndromes is presented. A broad survey of 92 panicoid species was sampled for the grass-specific insert sequence in the chloroplast RNA polymerase locus (rpoC2), combining published and unpublished sequences. This portion of the study also included an intensive phylogenetic investigation of one clade of seven species that included Steinchisma hians, which is notable for exhibiting intermediacy between the C3 and C4 photosynthetic types. Both rpoC2 data and previously published sequences of the F subunit of an NADH-dependent dehydrogenase were analyzed together for this small group. A rigorous phylogenetic investigation of S. hians and 13 other species of Panicoideae included in the broad survey was then performed with sequences of both rpoC2 and the externally transcribed spacer region of the nuclear ribosomal repeat. These 14 species were selected to maximize representation among photosynthetic subtypes. Combined analysis resolved single origins of two photosynthetic subtypes. A reversion of C4 to C3 photosynthesis during the evolution of the lineage that includes S. hians is identified. These and other recent results indicate that repeated reversions from C4 to C3 have occurred. The C3 species Panicum laxum has a strongly supported sister group relationship to S. hians (C3-C4). The most parsimonious interpretation is that S. hians represents an incipient reversal from C3 to C4 photosynthesis, beginning with the capacity to compartmentalize photorespiratory metabolism in the bundle sheath tissue

DAHLIA NEGLECTA (ASTERACEAE: COREOPSIDEAE), A NEW SPECIES FROM SIERRA MADRE ORIENTAL, MEXICO

Volume: 20Start Page: 593End Page: 59

Detecting Algal Contamination in Angiosperm DNA Extractions

Abstract. In molecular-based studies, universal PCR primers are effective due to their wide range of applicability. Unfortunately, this type of non-specific amplification can also be a drawback when DNA contaminants are unknowingly amplified. The internal transcribed spacer regions between the nuclear genes for ribosomal RNA are flanked by highly conserved genes. PCR primers for these genes have been shown to complementary base-pair with organisms from three kingdoms: Protista, Fungi, and Plantae. Current DNA extraction methods extract all DNA within and on an organism, regardless of its origin. This research project focuses on developing procedures for detecting algal DNA contaminants in angiosperm DNA extractions. This technique will be helpful for studies that include wet-climate or aquatic plants, which are especially susceptible to algal contamination. Key words: algal contamination, DNA extraction, angiosperm DNA, aquatic plant

VALIDATION OF THE NAME DAHLIA SUBLIGNOSA (ASTERACEAE)

Volume: 22Start Page: 545End Page: 54

DAHLIA SUBLIGNOSA (ASTERACEAE): A SPECIES IN ITS OWN RIGHT

Volume: 21Start Page: 2161End Page: 216

Dahlia campanulata and D. Cuspidata (Asteraceae, Coreopsideae): two new species from M\ue9xico

Volume: 64Start Page: 19End Page: 2

Status of Morus murrayana (Moraceae)

Volume: 94Start Page: 245--25

MORUS MURRAYANA (MORACEAE): A NEW MULBERRY FROM EASTERN NORTH AMERICA

ABSTRACT Mulberry trees (Morus: Moraceae) growing in relatively undisturbed, open woodland areas of western Kentucky exhibit exceptionally large leaves (blades often >15 cm long). Fruit size is also longer than reported for other species, and leaf vein patterns are unique. KEY WORDS: Morus, Moraceae, mulberry, murrayana, Kentucky, internal transcribed spacer, ITS Mulberry trees (Morus L.: Moraceae) in western Kentucky and the surrounding states, identified as M. rubra L., were observed with exceptionally large leaves. In a search of plant key