All published information on the Andean Velloziaceae is summarized and augmented by our own data obtained by revision of herbarium material, studies of cultivated plants and observations in the field. A new species from the central Andes within the department of Santa Cruz, Bolivia, is described and illustrated. Vellozia andina sp. nov. is distinguished by, among other characteristics, short, stout and trigonous stems and by the irregular pollen aggregates of more than eight grains. Habitat and ecology of the new taxon are described. This first Andean record considerably amplifies the known range of the genus Vellozia. The new species is a poikilohydrous and poikilochlorophyllous resurrection plant. Within the exclusively Andean genus Barbaceniopsis four species are recognized. Barbaceniopsis castillonii comb. nov., found in southern Bolivia and northern Argentina, with blue-violet and triangular-acute tepals forming a hypanthium, is differentiated from B. boliviensis, which has white, shorter, rather obtuse tepals and a shorter hypanthium. For both taxa new biological information and illustrations are provided. A distribution map and an identification key for all Andean Velloziaceae are presented.

Communicating Editor: John V. Freudenstein

Asarum sect. Asarum is a monophyletic group of 14 species distributed through North America, Europe, and Asia. The section is here treated in a taxonomic monograph based on morphological study of field-collected material and herbarium specimens. A key, descriptions, distribution maps, and citations of representative specimens are provided, and available information is reviewed on the pollination biology and phylogenetic relationships within the group. Six species of sect. Asarum are recognized in North America: A. canadense is widespread in the east, and the others range from widespread to narrow endemics in the west. Asarum canadense, which has at times been divided into several species or infraspecific taxa, is here recognized as a single species based on a lack of reliable differences among the variants. Asarum europaeum, which is the most widespread species in the section, has been similarly split historically, but also is treated here as a single taxon. In Asia, section Asarum consists of seven species from the eastern Himalayas through southeastern China, with two also extending into Japan.

Communicating Editor: Jeff H. Rettig

Corynocarpaceae group closely with Coriariaceae and Cucurbitaceae by axial parenchyma types (vasicentric scanty plus apotracheal banded plus ray-adjacent, all in strands of 1–2 cells) and Homogeneous Type II rays. Begoniaceae, Datiscaceae s. s., and Tetramelaceae group on the basis of absence of banded axial parenchyma and subdivision of the vasicentric parenchyma into strands of 3–5 cells. All of the families of Cucurbitales (except Anisophylleaceae) have two unusual features: minimal borders on perforation plates and unusually wide multiseriate rays (not accompanied by uniseriate rays). All of the families except Anisophylleaceae have another unusual feature, storied fusiform cambial initials. Anisophylleaceae have several wood features more primitive than those of other Cucurbitales (tracheids, aliform axial parenchyma, nonstoried cambial initials), but the family is not necessarily excluded from Cucurbitales. Data on wood of Corynocarpaceae are derived from samples of three species of Corynocarpus; possible specific characters are offered.

Communicating Editor: Richard Jensen

Sphagnum troendelagicum is only known from five localities in central Norway. Three populations were analyzed to assess its genetic affinities with other Sphagnum species. Isozyme and cytological data indicate that the species is allopolyploid. Morphological, RAPD, and isozyme data further indicate that it has originated from hybridization between Sphagnum tenellum (sect. Mollusca) and S. balticum (sect. Cuspidata). Sphagnum troendelagicum is morphologically distinct, with unique combinations of character states found in sect. Cuspidata and sect. Mollusca. Sphagnum tenellum is genetically similar to S. balticum, although these species are morphologically divergent. Our data support the inclusion of S. tenellum within sect. Cuspidata. Sphagnum troendelagicum appears to have originated recurrently; thus its restricted distribution cannot be ascribed to a single origin. The progenitor species are widespread in the Northern Hemisphere and often grow sympatrically in boreal areas. Hypotheses that may account for the restricted distribution of S. troendelagicum, including ecological tolerance of the allopolyploid and opportunities for hybridization between the progenitors, are discussed.

Communicating Editor: Kathleen A. Kron

Communicating Editor: Kathleen A. Kron

Because geographic races occupy pivotal niches in both evolutionary theory and taxonomy, species for which races or infraspecific taxa have been identified may provide the best cases for evaluating models of geographic speciation. Despite its relatively restricted geographic distribution, Leptodactylon californicum exhibits morphological variation that has been recognized at the infraspecific level. Five subspecies have been recognized within this California endemic, each adhering to specific geographic limits and reportedly exhibiting distinguishing morphological features. We investigated geographic divergence among populations of L. californicum through examination of patterns of divergence in morphology, allozymes, and ribosomal DNA profiles. Geographic trends in morphology have previously been reported, with clines running from north to south and from the Pacific coast inland. Correlations between genetic (i.e., allozymic) divergence and morphology, genetic divergence and geographic location, and morphology and geographic location were detected. Gene flow among populations appears to be restricted, most likely due to geographic barriers, permitting the divergence of populations. Divergence may be further enhanced by self-pollination. Unique alleles are fixed in the most geographically isolated populations; these populations are also the most divergent morphologically. No variation in rDNA restriction sites was detected among populations. The allozyme data, coupled with morphology, support a model of geographic divergence in L. californicum and provide the basis for reassignment of subspecific designations within the species.

The chloroplast trnL-F region was sequenced for 20 species of Velloziaceae sensu stricto plus Acanthochlamys and representative species of Cyclanthus (Cyclanthaceae) and Pandanus (Pandanaceae) as outgroups. Phylogenetic analysis of the trnL intron and trnL-F intergenic spacer placed the Asian Acanthochlamys as a distant but well-supported sister-group to a monophyletic Velloziaceae sensu stricto. Within the Velloziaceae, the subfamily Barbacenioideae sensu Menezes is well supported as monophyletic, in agreement with chromosomal and morphological data, while the subfamily Vellozioideae may be paraphyletic. At least two of the currently recognized genera within the Barbacenioideae (Aylthonia and Barbacenia) appear to be paraphyletic or polyphyletic as currently delimited, while the genus Burlemarxia appears to have arisen recently within a subgroup of Barbacenia. These results appear most consistent with the inclusion of all or almost all of the taxa of the Barbacenioideae within a broadly delimited genus Barbacenia. Within the subfamily Vellozioideae, trnL-F data are consistent with the segregation of the South American Nanuza from Vellozia as a distinct genus, while the South American species sometimes placed in Xerophyta are not distinct from Vellozia.

Communicating Editor: John V. Freudenstein

Relationships of the enigmatic genera Whitfieldia, Chlamydacanthus, and Lankesteria (Acanthaceae) were examined using molecular sequence data for two chloroplast loci (ndhF gene, trnL-trnF spacer and intron) for these and a sample of taxa representing all major lineages within the family. Morphological data, including pollen structure as imaged using SEM, were also compiled for these three genera, and evaluated in a phylogenetic context. Bremekamp suggested that Whitfieldia and Chlamydacanthus belonged together as tribe Whitfieldieae, and that Lankesteria was closely related to Pseuderanthemum in Justicieae. Contra earlier classifications of Acanthaceae, this would result in tribes with multiple corolla aestivation patterns. Our results confirm that Chlamydacanthus and Whitfieldia are closely related. Unexpectedly, Lankesteria is sister to these two genera together and we propose that the three genera comprise an expanded tribe Whitfieldieae. Also unexpectedly, Whitfieldieae is sister to Barlerieae. We propose a number of morphological synapomorphies for Whitfieldieae including concentric rings of ridges on the seeds and a densely granular circular area surrounding the pores of pollen grains. Chlamydacanthus and Whitfieldia further share biporate, flattened pollen grains that are circular in outline, and seeds with glabrous surfaces. Barlerieae is a large and diverse lineage such that synapomorphies to support aspects of their relationships are difficult to identify. However, hygroscopic trichomes on the seeds may be a synapomorphy for Whitfieldieae plus Barlerieae, with subsequent loss in Chlamydacanthus, Whitfieldia, and some Barleria. As here circumscribed, Whitfieldieae includes plants with both contort and imbricate corolla aestivation seconding Bremekamp's misgivings about basing classifications entirely upon this character.

Communicating Editor: Richard Jensen

The systematic relationships of four species in the South African holoparasitic genus Hyobanche were examined using inter-simple sequence repeat (ISSR) banding patterns and nucleotide sequence data from nuclear ribosomal ITS regions and the plastid gene rbcL. Ordination of ISSR data revealed discrete groups, although H. glabrata and H. rubra were indistinguishable. Phylogeny reconstructions based on ISSR and ITS data were congruent and depicted relationships where H. atropurpurea and H. sanguinea form a clade with H. glabrata and H. rubra as their sister group. In contrast, the rbcL tree revealed a topology where H. atropurpurea was sister to a clade that included the other three species. The combination of molecular, morphological, and biogeographical data suggest two alternative hypotheses: (1) that floral evolution has progressed from galeate hirsute corolla tubes to straight glabrous tubes as represented by H. sanguinea, H. glabrata (intermediate morphology), and H. rubra, respectively; or (2) the intermediate floral morphology and distribution of H. glabrata reveal a hybrid origin of this species with H. sanguinea and H. rubra as progenitors.

Communicating Editor: Paul Wilson

Phylogenetic relationships within subfamily Arbutoideae (Ericaceae) were estimated using parsimony and maximum likelihood analyses of sequence data from the ITS region and part of the large subunit of nuclear ribosomal DNA. The data support the monophyly of Arctostaphylos, Arctous, and Comarostaphylis, but suggest that Arbutus is not monophyletic, with Mediterranean Basin species more closely related to the clade containing Arctostaphylos, Arctous, Comarostaphylis, Ornithostaphylos, and Xylococcus than to the western North American species of Arbutus. Calibration of branch lengths with the fossil record suggests that a vicariance event occurred among members of the Arbutoideae between western North America and the Mediterranean Basin at the Paleogene/Neogene boundary, consistent with the Madrean-Tethyan hypothesis.

Communicating Editor: Kathleen A. Kron

Phylogenetic analyses of ITS sequence data from 70 species and 40 genera of Araliaceae (representing all major lineages within the “core group” of the family) do not support the widely used traditional division of Araliaceae into three tribes. Tribe Aralieae (characterized by imbricate petals) is found nested within a paraphyletic Schefflerieae (whose taxa have valvate petals). There are, however, two large monophyletic groups comprising most araliad genera: the ”Aralia-Polyscias-Pseudopanax group” (which includes Aralia, Meryta, Munroidendron, Panax, Pentapanax, Polyscias, Pseudopanax, Reynoldsia, Sciadodendron, Tetraplasandra, and their close allies), and the ”Eleutherococcus-Dendropanax-Schefflera group” (including Brassaiopsis, Dendropanax, Eleutherococcus, Fatsia, Hedera, Oreopanax, Schefflera, Sinopanax, and their close allies). The ITS trees also permit a re-evaluation of several taxonomically important morphological characters (e.g., petal aestivation, leaf architecture, carpel number, and habit), and provide the opportunity to assess traditional generic delimitations in the family. Four of the largest genera appear to be either polyphyletic (Schefflera, Pseudopanax) or paraphyletic (Aralia, Polyscias), but further studies will be needed to fully re-define these complex taxa. Outgroup comparisons and the placement of Astrotricha and Osmoxylon (in basally-branching lineages in Araliaceae) help to confirm a paleotropical origin of the family. The ITS topologies suggest that biogeographic radiations into different tropical/subtropical regions and into the north and south temperate regions occurred early in the history of core Araliaceae. Temperate taxa have arisen several times independently from tropical and subtropical relatives, although a few subtropical taxa may be found nested within temperate clades (e.g., Pentapanax within Aralia). Migrations between the Old and New Worlds are also suggested for several taxa, including Aralia, Panax, Oplopanax, and the Sinopanax—Oreopanax generic pair.

Communicating Editor: Alan Whittemore

The apparent recency of diversification of Californian Lessingia (Compositae, Astereae) makes the genus a particularly interesting group for evolutionary investigation. Here we focus on the major evolutionary lineages within Lessingia (sensu Lane 1992) and the higher-level relationships of the genus and presumed close relatives using sequence data from the 18S–26S nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region and the 3’ end (561–563 bp) of the external transcribed spacer (ETS). We present new 3‘ETS primers that are useful across Astereae and examine the phylogenetic utility of the 3‘ETS in Lessingia and close relatives. In Lessingia, the 3‘ETS region appears to have evolved up to 1.4 times more rapidly by nucleotide substitution than has the ITS region. Our results show that data from the ETS greatly augments data from the ITS region; the combined data set yields the best resolved and best supported molecular trees for Lessingia. These topologies lead us to five conclusions regarding the phylogenetic relationships of Lessingia (sensu Lane 1992) and closely related genera: (1) Lessingia may not be monophyletic when Benitoa is included within the genus, (2) among the taxa sampled, Benitoa and Hazardia appear to be the closest living relatives of Lessingia s. s. and L. filaginifolia (= Corethrogyne), (3) a sister group relationship exists between the radiate, perennial L. filaginifolia (= Corethrogyne) and the discoid, annual members of the genus (Lessingia s. s.), (4) different corolla coloration (pink/white vs. yellow) diagnoses the two major clades of Lessingia s. s., and (5) the “yellow group” of lessingias comprises three distinct, morphologically diagnosable, lineages which span the currently accepted circumscriptions of two taxa (L. lemmonii and L. glandulifera).

Communicating Editor: Kathleen A. Kron

Communicating Editor: Aaron Liston

Mosaically sympatric populations of Blepharizonia plumosa subsp. plumosa and B. plumosa subsp. viscida occur in the eastern San Francisco Bay region, California. Results from pollen and chromosomal studies of artificial hybrids yielded evidence of low interfertility between individuals of different taxa. Low fertility of hybrids between taxa was associated with meiotic irregularities (e.g., failure of meiosis I). Phylogenetic analyses of 18S–26S nuclear ribosomal DNA sequences of the internal transcribed spacer (ITS) region from representatives of multiple populations of both groups yielded evidence for two well-supported evolutionary lineages corresponding to B. plumosa subsp. plumosa and B. plumosa subsp. viscida. Pairwise distances between ITS sequences of the two taxa approximate or exceed pairwise ITS sequence distances between species of tarweed genera that are closely related to Blepharizonia. Rate constancy of ITS sequence evolution allowed us to estimate a five-fold more ancient divergence between lineages corresponding to the two taxa in Blepharizonia than between lineages corresponding to the two outgroup taxa in Hemizonia. We conclude that the two taxa currently recognized in Blepharizonia are ancient, highly divergent groups worthy of continued taxonomic recognition and best treated as species, B. plumosa and B. laxa (= B. plumosa subsp. viscida). Although natural hybridization appears to occur between B. laxa and B. plumosa, we found no convincing evidence of introgression that could lead to loss of genetic integrity of the rare and endangered B. plumosa.