New and noteworthy plants from Great Barrier Reef sand cays,Australia

Observations are presented on new and critical plants from the northern sand cays on the Great Barrier Reef, Queensland, Australia, based mainly on recent collections made by David R. Stoddart and Ralf Buckley. New species and varieties are described:Lepturus stoddartii (Poaceae),Boerhavia fistulosa var.fistulosa and var.puberuliflora (Nyctaginaceae),Boerhavia albiflora var.heronensis, Spermacoce everistiana (Rubiaceae), andSpermacoce buckleyi; a new combination is made:Diospyros ferrea var.compacta (R. Br.) (Ebenaceae); and additional taxonomic notes are given onBoerhavia, Euphorbia (Euphorbiaceae), andAbutilon (Malvaceae).     

New combinations for Panicum subgenus Panicum and subgenus Dichanthelium (Poaceae) of the Southeastern United States

Twenty-two new varietal combinations are made for the treatment of the genusPanicum of the Southeastern United States. The following 3 new combinations are made in the subgenusPanicum:Panicum rigidulum var.elongatum, P. rigidulum var.pubescens, P. rigidulum var.combsii. The following 19 new combinations are made in the subgenusDichanthelium:P. strigosum var.glabrescens P. strigosum var.leucoblepharis, P. dichotomum var.roanokense, P. dichotomum var.lucidum, P. dichotomum var.ramulosum, p. dichotomum var.mattamuskeetense, P. dichotomum var.yadkinense, P. ensifolium var.curtifolium, P. chamaelonche var.breve, P. portoricense var.nashianum, P. acuminatum var.fasciculatum, P. acuminatum var.unciphyllum, P. acuminatum var.columbianum, P. acuminatum var.lindheimeri, P. acuminatum var.densiflorum, P. acuminatum varlongiligulatum, P. acuminatum var.leucothrix, P. ovale var.pseudopubescens, andP. ovale var.villosum.     

Three new species of Dasylirion (Nolinaceae) from Mexico and a clarification of the D. longissimum complex

Three new species ofDasylirion and a new variety ofD. longissimum Lem. from the mountains of northern Mexico are described and illustrated. Two of the new species are from northwestern Mexico:D. gentryi, with large, rosecolored fruits and glossy, non-waxy leaves; andD. sereke, characterized by roundish fruits with an unusuall large style.Dasylirion miquihuanense is a new species from northeastern Mexico with narrow, strictly upright leaves and widely separated marginal prickles. TheDasylirion longissimum complex consists of two species,D. quadrangulatum S. Wats andD. longissimum Lem., characterized by narrow, quadrangulate leaves with reduced or absents marginal prickles. Distinguishing features of these two species, which have often been confused, are presented andD. longissimum var.treleasei, characterized by small flowers and fruits, is described.     

New combinations and one new variety among the genera Indigofera,Robinia, and Tephrosia (Leguminosae)

This report includes: a new variety,Indigofera miniata var.florida, and five new combinations.I. mucronata var.keyensis, Robinia hispida var.kelseyi, Tephrosia angustissima var.corallicola, T. angustissima var.curtissii, andT. × floridana.     

New taxa in Pectis (Compositae: Pectidinae) from Mexico and the southwestern United States

Pectis minutiflora,P. papposa var.grandis, andP. purpurea var.sonorae are described as new. A new combination,P. purpurea var.lancifolia also is included. Chromosome counts (n = 12) are reported forP. papposa var.grandis andP. purpurea var.sonorae.     

Two shrubby novelties in Eriogonum (Polygonaceae) from the deserts of Utah and Arizona

Two desert shrubs belonging toEriogonum subgen.Eucycla sect.Corymbosa are described from southern Utah and northern Arizona.Eriogonum mortonianum, endemic to red clay hills southwest of Fredonia, in extreme northeastern Mohave County, Arizona, is most closely related toE. smithii, a species endemic to the San Rafael Desert of Emery County, Utah, but differs in having wider leaves, a much more branched inflorescence, and smaller, pale-yellow or white flowers.Eriogonum leptocladon var.papiliunculi, found in central Garfield and eastern Kane counties, Utah, southward into northern Coconino and Navajo counties, Arizona, is distinguished from var.leptocladon by its white flowers and from var.ramosissimum by its glabrous stems.     

A new name and new combinations in Campomanesia and Pimenta (Myrtaceae)

One new name is proposed and eleven new combinations are made inCampomanesia andPimenta. Lectotypes are selected forC. eugenioides var.desertorum, C. phaea, andP. racemosa var.hispaniolensis, var.ouza, and var.terebinthina.     

A new variety of coreopsis mutica (Compositae) from Mexico

Coreopsis mutica var.simplicifolia is described from the state of Guanajuato in Mexico. The new variety is distinguishable by its simple lanceolate to linear-lanceolate leaves. In addition, var.simplicifolia is al lopatric with other C.mutica and has a distinctive leaf flavonoid chemistry. The chromosome number of the variety is 2n = 56.     

New taxa and combinations in Malvastrum A. Gray (Malvaceae: Malveae)

The genusMalvastrum A. Gray is interpreted to include 22 taxa in 14 species. Seven taxa are here described as new, namely:M. americanum var.stellatum,M. tomentosum subsp.pautense,M. bicuspidatum subsp.campanulatum,M. bicuspidatum subsp.oaxacanum, M. bicuspidatum subsp.tumidum var.tumidum, M. bicuspidatum subsp.tumidum var.glabrum, andM. coromandelianum subsp.fryxellii. In addition, two new combinations are proposed, namely:M. tomentosum andM. coromandelianum subsp.capitato-spicatum.     

New names,combinations, and lectotypifications in Heterotheca (Compositae: Astereae)

The following new names and combinations are proposed:Heterotheca barbata (Rydb.) Semple,H. horrida subsp.cinerascens (S. F. Blake) Semple,H. fulcrata vararizonica Semple,H. fulcrata var.senilis (Wooton & Standley) Semple,H. oregona var.compacta (Keck) Semple,H. oregona var.rudis (Greene) Semple,H. oregona var.scaberrima (A. Gray) Semple,H. pumila (Greene) Semple,H. villosa var.pedunculata (Greene) V. Harms ex Semple, andH. zionensis Semple. The following chromosome numbers are reported for the first time:H. fulcrata var.arizonica, 2n=9 _II ;H. horrida subsp.cinerascens, 2n=18 _II ;H. pumila, 2n=9 _II ,2n=18 _II ;H. zionensis, 2n=9 _II .     

Taxonomic and nomenclatural notes on west Indian hypnaceae

Taxonomic investigations on the West Indian Hypnaceae have resulted in the following new taxa,Taxiphyllum gallorum, Ectropothecium aquaticum, andIrelandia (forIsopterygium robusticaule). Vesicularia in the West Indies is treated as a single species with four varieties,V. vesicularis var.vesicularis, var.rutilans (Brid.) comb. nov., var.portoricensis (Brid.) comb. nov., and var.crassicaulis (Mitt.) comb. nov.Chryso-hypnum is segregated fromMittenothamnium; the combinationC. diminutivum (Hampe) Buck is made.     

Changes and additions in ipomoea section batatas (Convolvulaceae)

A new species, Ipomoea tabascana, is described from Mexico, and the combination I. batatas var. apiculata is made for plants endemic to Veracruz. Comments on the alliance of I. umbraticola with the section Batatas are given.     

New combinations in Hawaiian Chamaesyce (Euphorbiaceae)

Chamaesyce is accepted at the genus level for the Hawaiian taxa. The following new combinations are made:C. celastroides var.laehiensis, C. celastroides var.tomentella, C. rockii var.grandifolia, C. skottsbergii var.vaccinioides, andC. sparsiflora.     

Taxonomy of Gundlachia (Compositae: Astereae)

Gundlachia, a genus of shrubs occurring in the Caribbean islands, is treated as comprising two species, one of which has six varieties. Five new combinations are made: Gundlachia corymbosa var. apiculata (Britton & S. F. Blake) M. A. Lane, G. corymbosa var. compacta (Urb. & Ekman) M. A. Lane, G. corymbosa var. cubana (Britton & S. F. Blake) M. A. Lane, G. corymbosa var. foliosa (Britton & S. F. Blake) M. A. Lane, and G. corymbosa var. ocoana (Urb. & Ekman) M. A. Lane. Gundlachia is probably most closely related to Gymnosperma.     

A new variety of trillium pusillum (Liliaceae) from the Virginias

A montane population ofTrillium pusillum Michx. from the crest of Shenandoah Mountain on the Virginia-West Virginia state line is newly described asT. pusillum var.monticulum. It differs from the related coastal plain variant, var.virginianum Fernald, by its broader and shorter leaf and sepal ratios, typically notched petal apices, consistently sessile flowers (not at all pedicellate), slightly shorter style, and reduced stature. The var.monticulum is restricted to the ridge crest of the mountains at 1190 m (3900 ft) elevation while the var.virginianum is restricted to the coastal plains of eastern Maryland and Virginia et elevations less than 30 m (100 ft).     

A new variety of cardamine angustata (cruciferae) from the Ouachita Mountains of Arkansas

Cardamine angustata var.ouachitana E. B. Smith, a new variety differing fromC. angustata var.angustata in absolutely glabrous leaf segments, is described from the Ouachita Mountains of Arkansas.     

New varietal combinations in Agave vivipara (Agavaceae)

New varietal combinations are made inAgave vivipara forA. deweyana, A. letonae, A. nivea, A. rubescens andA. angustifolia var.sargentii. A. angustifolia var.marginata andA. angustifolia var.variegata are transferred toA. vivipara as cultivars.     

Overexpression of profilin 3 affects cell elongation and F-actin organization in Arabidopsis thaliana

Key message

Reduced levels of profilin 3 do not have a noticeable phenotypic effect; however, elevated profilin 3 levels result in decreased hypocotyl length due to a reduction in cell elongation and F-actin reorganization.

Abstract

The actin cytoskeleton is critical for a variety of cellular processes. The small actin monomer proteins, profilins (PRFs), are encoded by five highly conserved isoforms in Arabidopsis thaliana. PRF3, one of the vegetative isoforms, has 36 more N-terminal amino acid residues than the other four PRFs; however, the functions of PRF3 are mostly unknown. In this study, we demonstrated that PRF3 was strongly expressed in young seedlings, rosette leaves, and cauline leaves, but was weakly expressed in 14-day-old seedlings and flowers. Our data also showed that PRF3 could increase the critical concentration (Cc) of actin assembly in vitro. Overexpression of the full-length PRF3 cDNA resulted in a decrease in the lengths of roots and hypocotyls and delayed seed germination, but PRF3-ΔN36 transgenic plants and prf3 mutant plants showed normal growth when compared with wild-type plants. Microscopy observation revealed that cell elongation was inhibited in the hypocotyl and that F-actin was reorganized by destabilizing microfilaments. These results suggest that the dwarf phenotype of the PRF3 overexpression seedlings may be related to a reduction in cell length and F-actin rearrangement.     

Notes on endangered buckwheats (Eriogonum: Polygonaceae) with three newly described from the western United States

Three unnamed buckwheats listed by the United States Fish and Wildlife Service in December 1980 as potentially endangered or threatened plants are formally proposed:E. crosbyae from Lake Co., Oregon;E. grande var.dunklei from San Miguel Island, Santa Barbara Co., California; andE. ovalifolium var.williamsiae from Washoe Co., Nevada. Several other species proposed by the Fish and Wildlife Service as potentially endangered or threatened (E. allenii, E. correllii, E. eremicum, E. floridanum, E. lemmonii, E. sp./sp. nov. ined. [=E.libertini], E. tumulosum, E. umbellatum var./var. nov. ined.,E. umbellatum var.minus, E. vestitum, andE. zionis var.coccineum) are discussed and evidence is given why they cannot be considered endangered or threatened under the present Endangered Species Act of 1973, as amended.