Section Racemosae Research Articles

Carex hartmaniorum (Cyperaceae), a new species for the Spanish flora

Carex hartmaniorum (sect. Racemosae, Cyperaceae) is reported for the first time for Spain, from a single known population in the Cerdanya region (Eastern Pyrenees, Girona province). The main differences with closely related taxa are highlighted, a dichotomous key to differentiate this species from members of section Racemosae inhabiting the Iberian Peninsula and the Pyrenees is presented, and some comments on its distribution and ecology are made. A preliminary conservation assessment for Spain resulted in the proposal of the Endangered category of C. hartmaniorum for Spain.

Taxonomic revision of Sobralia section Racemosae Brieger (Sobralieae, Orchidaceae)

Sobralia Ruiz & Pav. is a large and morphologically diverse neotropical orchid genus. It can be divided into four sections and some informal groups of species based mainly on the inflorescence architecture. While most of the species have strongly abbreviated, compact raceme, the section Racemosae is characterized by an elongated inflorescence with distinct internodes between flowers. Although the group is well-defined and easily distinguishable in terms of morphology, its species are often similar to each other and may be easily misidentified. Identification is especially difficult when considering herbarium specimens. Here, a taxonomic revision of Sobralia section Racemosae is presented. Apart from particular species’ morphological characteristics, keys for identification, ecological data, and distribution maps are presented. Sobralia gambitana is described as a species new to science. A neotype for S. hoppii Schltr. is proposed.

<p><strong>A NEW MASDEVALLIA FROM SOUTH-WESTERN COLOMBIA (ORCHIDACEAE: PLEUROTHALLIDINAE) </strong></p>

A new species belonging to Masdevallia section Racemosae is described from South-Western Colombia. It is very similar to Masdevallia racemosa, the only other member of the section, with which it shares the characteristic repent habit, loose multi-flowered inflorescence, and striking red-orange flowers. However, Masdevallia mirandae can be distinguished by the adaxially hispid sepals and the elliptic petals with a rounded apex. The new species is restricted to The Farallones de Cali National Natural Park and its populations are threatened by illegal mining activities.

Morphological variability and genetic diversity in Carex buxbaumii and Carex hartmaniorum (Cyperaceae) populations.

BackgroundCarex buxbaumii and C. hartmaniorum are sister species of the clade Papilliferae within the monophyletic section Racemosae. An unambiguous identification of these species is relatively difficult due to the interspecific continuum of some morphological characters as well as the intraspecific variability. The study was aimed at determining the range of variability, both morphological and genetic, within and between these two closely related and similar species.MethodsThe sedges were collected during botanical expeditions to Armenia, Estonia, the Netherlands, and Poland. The morphological separation of the two species and their populations was tested using the Discriminant Function Analysis (DFA). The genetic variability of the 19 Carex populations was assessed in the presence of eight Inter Simple Sequence Repeat (ISSR) primers.ResultsResults of the study indicate a considerable genetic affinity between the two sedge species (mean Si = 0.619). However, the populations of C. hartmaniorum are, morphologically and genetically, more homogenous than the populations of C. buxbaumii. Compared to C. hartmaniorum, C. buxbaumii usually has wider leaf blades, a shorter inflorescence, a lower number of spikes which are shorter, but wider, and longer bracts and utricles. The AMOVA showed a larger variation between the populations of C. buxbaumii, representing 25.65% of the total variation in the taxon. Two populations of C. buxbaumii (from Poland and Estonia) are separated from the remaining populations, both genetically and morphologically; their individuals show shorter utricles and glumes, compared to the typical specimens of C. buxbaumii, and correspond with the morphology of putative infraspecific taxa described by Cajander (var. brevisquamosa and var. confusa).ConclusionsThe taxonomic status of the putative infraspecific taxa within C. buxbaumii requires further studies throughout the distribution range of C. buxbaumii, addressing habitats, morphology and genetics (including a chromosome count or a combination of different genetic methods), particularly as the variability in C. buxbaumii may be associated with the species’ polyploid origin.

A New Remarkable Dwarf Sedge (Carex phylloscirpoides, Cyperaceae) from Northern Chile, with Insights on the Evolution of Austral Carex section Racemosae

Abstract—We describe a new remarkable dwarf and apparently acaulescent species of Carex (Cyperaceae) from the Andes of northern Chile: Carex phylloscirpoides. Morphological and molecular data (two nuclear and three plastid DNA regions) were used to study the phylogenetic placement and systematic relationships of this species, which resulted in its assignment to Carex section Racemosae. However, despite being related to the other three species of the section present in the Southern Cone based on phylogenetic evidence, it displays a number of unusual morphological features. In addition, it is geographically disjunct and genetically differentiated from them. A preliminary conservation assessment was performed which resulted in the proposal of the Critically Endangered category at the global level under IUCN guidelines. We discuss the biogeographic and ecological peculiarities of the new species and its allies, with emphasis in the high number of acaulescent sedges present in South America. The features of C. phylloscirpoides emphasize its unique evolutionary position and its rarity highlights its conservation importance, especially in the context of the South American Andean flora.

Bulbophyllumchrysolabium (Orchidaceae, Epidendroideae, Malaxideae), a new species from Yunnan, China.

Bulbophyllumchrysolabium, a new species belonging to section Racemosae from Yunnan, China is described and illustrated. The species is related to B.orientale and B.morphologorum, but differs by having the following set of characters: obliquely broadly-based triangular petals with a long filiform apex; lip densely glandular papillose and conspicuously ciliolate along margins; lip auricles well developed, narrowly falcate, tapering to a long sharp point at the apex; stelidia subulate and twisted inwards, slightly exceeding operculum. The conservation status of B.chrysolabium is assessed and taxonomic notes are provided.

Evidence for the Dual Role of Floral Secretory Cells in Bulbophyllum

Abstract Floral epidermal cells of most species of Bulbophyllum Thouars studied to date produce both lipid-rich food-rewards and fragrance. Since fragrances largely consist of terpenoids and have an affinity for lipophilic stains, the simultaneous presence of lipid-rich food-rewards frustrates identification of fragrance-secreting cells by conventional histochemistry. Furthermore, since both lipid-rich food-rewards and fragrances are probably synthesized by a similar complement of organelles, interpretation of TEM images can prove difficult. All members of section Racemosae Benth. & Hook. f. investigated to date, however, are unusual in their secretion of a predominantly proteinaceous food-reward, and lipids are seemingly absent. This might enable their use as models for the identification and characterization of fragrance-secreting tissues and organelles. Three members of sect. Racemosae were chosen, namely Bulbophyllum dissitiflorum Seidenf., B. lilacinum Ridl. and B. tricorne Seidenf. & Smitinand. All produced food-rewards. Of these, one (B. dissitiflorum) lacked fragrance and was used as a control, whereas the remaining two species produced fragrance. Having established that the food-reward was mainly proteinaceous in each case, and did not test positively for lipid, we undertook further histochemical investigations, as well as light microscopy, SEM and TEM. Specialized palisade-like epidermal cells of all species contained protein bodies and rough endoplasmic reticulum consistent with the production and secretion of a protein-rich food-reward. Cuticular pores were also present. In fragrant species, these cells also contained abundant smooth endoplasmic reticulum, oil droplets and many, well-developed, spherical plastids with numerous plastoglobuli, similar to those found in the osmophores (fragrance-producing structures) of other orchids. Indeterminate, osmiophilic cytoplasmic inclusions were also present. By contrast, the non-fragrant species lacked oil droplets and other osmiophilic inclusions and the plastids were scant, poorly developed, often elongate or irregular in shape and contained few plastoglobuli. Smooth endoplasmic reticulum was also less frequent. Since food-rewards tested negatively for lipid, it is probable that any oil droplets present were involved in fragrance production, especially since they were absent from the non-fragrant species. Thus, the unusual absence of lipids from the food-rewards of sect. Racemosae provided a rare opportunity, permitting, for the first time, the unraveling of these two secretory processes (food-reward and fragrance) in Bulbophyllum and clearly demonstrating the plasticity of these cells and their dual role in secretion.

CarexsectionRacemosae(Cyperaceae) in Europe: morphological diversity, taxonomy and phylogenetic relationships

All European taxa of Carex section Racemosae were assessed using macromorphological (mainly quantitative) and micromorphological characters (sculpture of utricles and nutlets). Morphological separation of the specimens examined was tested using discriminant function analysis (DFA). Micromorphology of utricles and nutlets was investigated using scanning electron microscopy (SEM). The results show that: (1) C. bicolor differs from other taxa in section Racemosae in macro- and micromorphological characters, justifying removal of the species from the section; (2) the morphological data support placing C. stylosa in a separate section, Stylosae; (3) morphologically, C. holostoma has a close affinity with taxa in subsection Papilliferae; (4) C. parviflora differs significantly from the remaining members of subsection Alpinae in the size and colour of the utricles and we suggest reconsidering the position of this species in subsection Alpinae; (5) morphological characters are insufficient for maintaining C. norvegica subsp. pusteriana and C. norvegica subsp. norvegica at subspecies level; (6) C. atrata, C. aterrima and C. caucasica are morphologically well-defined and valid species; (7) C. aterrima subsp. aterrima and C. aterrima subsp. medwedewii are morphologically similar and their taxonomic status requires further study, also at the molecular level.

Utilizing RADseq data for phylogenetic analysis of challenging taxonomic groups: A case study in Carex sect. Racemosae.

Relationships among closely related and recently diverged taxa can be especially difficult to resolve. Here we use both Sanger sequencing and next-generation RADseq data sets to estimate phylogenetic relationships among species of Carex section Racemosae (Cyperaceae), a clade largely restricted to high latitudes and elevations. Interest in relationships among these taxa derives from questions about the species' biogeographic histories and possible links between diversification and Pleistocene glaciations. A combination of approaches and molecular markers were used to estimate relationships among Carex species within sect. Racemosae and taxa from closely related sections. Nuclear and chloroplast loci generated by Sanger sequencing were analyzed with *BEAST, and SNP data from RADseq loci were analyzed as a concatenated data set using maximum likelihood and as independent loci using SVDquartets. Sanger sequencing data sets resolved relationships among taxa at intermediate phylogenetic depths (albeit with low levels of support). Only the RADseq data resolved relationships with strong support at all phylogenetic depths. Moreover, different methods and data partitions of the RADseq data resulted in nearly identical topologies. Carex sect. Racemosae is a strongly supported clade, although a handful of species were found to group with closely related sections. Herbarium specimens up to 35 yr old successfully produced informative RADseq data. Despite the short read lengths of RADseq data, they nevertheless resolved relationships that Sanger sequencing data did not. Resolution of the phylogenetic relationships among recently and rapidly diversifying taxa within sect. Racemosae clades suggest a role for the Pleistocene glaciations in clade diversification.

A new species of Baccharis (Asteraceae: Astereae) and miscellaneous notes to Sect. Discolores and Racemosae

Bacccharis floccosa is described, illustrated and have their taxonomic affinities discussed. The new species belongs to section Discolores DC. emend. Cuatrec., and can be easy segregated of all species of this section by a combination of the following features: strongly discolorous leaves, pistillate capitula with 7-9 flowers, and corolla of staminate flowers at the apex clothed by filiform trichomes concentrated at the apex of the tube. The new species is related to sympatric species Baccharis nummularia Malme, but differs by its robust habit (1.5-2.5 m vs . 0.3-0.8 m high), attenuate leaves (vs. rounded), and smaller pistillate capitula, with peduncles densely floccose pubescent (vs. peduncles sericeous pubescent). From the allopatric species Baccharis phylicoides Kunth the new species differs by number of pistillate flowers per capitulum (7-9 vs. 13-65), indumentum on abaxial surface of the leaves consisting of a compact and dense layer ( vs . loose layer), and corolla of staminate flowers densely clothed by filiform trichomes concentrated at the apex of the tube. Baccharis floccosa displays range of geographical distribution smaller than 1,000 km 2 , beeing considered endangered species, according with the criteria of IUCN. Baccharis nummularia is added to section Discolores and a key to segretate the species of the section Discolores is given. Furthermore morphological features to set apart the sections Discolores and Racemosae Ariza are supplied, as well as Baccharis uncinella DC. and B . longittenuata A.S. Oliveira are positioned into the section Racemosae.

Vaucheria zapotecana (Xanthophyceae), a new species from Oaxaca, Mexico

Bonilla-Rodríguez M., Garduño-Solórzano G., Martínez-García M., Campos J.E., Monsalvo-Reyes A.C. and Quintanar-Zúñiga R.E. 2013. Vaucheria zapotecana (Xanthophyceae), a new species from Oaxaca, Mexico. Phycologia 52: 550–556. DOI: 10.2216/13-162.1A new species of Vaucheria was isolated from the Santa Gertrudis River in Oaxaca, Mexico. This taxon was distinguished from the other six species in the Pseudogeminata group of section Racemosae by wider siphonous filaments and antheridia of a larger diameter, lack of septa in the gametophore, broader oogonial beak, erect oogonia and oospores that lacked yellowish spots. This species was named Vaucheria zapotecana sp. nov. The phylogenetic relationship of this species was investigated by analyzing a 2022-base-pair sequence that included the rbcL gene; results revealed a close relationship among this species, V. pseudogeminata and other species of the section Racemosae; although, the sequence for V. zaptecana is distinct.

A new species ofEugenia(Myrtaceae) from north-eastern Brazil

A new species of Eugenia section Racemosae (Myrtaceae), Eugenia brejoensis Mazine, is described, illustrated and discussed. It is characterized by its pedunculate racemes, with greyish hairs, leaves with yellowish blade on the lower surface, glandular dots impressed to slightly prominent on the upper surface, pendant apex, and flowers with persistent and pubescent bracteoles. Eugenia brejoensis is known only from highland humid forests, locally called ‘brejo’, in the caatinga area of Pernambuco State, north-eastern Brazil. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 775‐777.

Phylogeny of the Afro-Madagascan Aristea (Iridaceae) revisited in the light of new data on pollen morphology

Scanning and electron microscopic studies of the pollen grains of several species of the sub-Saharan African and Madagascan genus Aristea of c. 50 species, supplement data from an earlier study and enable us to include these species in a phylogenetic analysis. TEM examination of a range of pollen grains of representative pollen types in Aristea makes it possible to reinterpret past SEM results so that apertures covered with exine masses and previously called sulculate, are now seen to be either zonasulculate or dizonasulculate. Revised and expanded data are combined in a matrix together with new data for seed morphology in the genus, which like the capsules is remarkably diverse, including angular seeds with reticulate sculpturing, lamellate or triangular-columnar seeds with smooth or reticulate surfaces and with smooth or papillate or areolate margins. This new phylogenetic analysis suggests that Aristea should remain treated as comprising three subgenera. In subgenus Eucapsulares we add a new section Latifolieae for A. latifolia, which seems an isolated relic restricted to the mountains of the Cape Region of South Africa, an area of winter rainfall. Species with similar unspecialized capsule and seed morphology occur only in eastern south and tropical Africa and Madagascar, but they have derived pollen morphology whereas the pollen of A. latifolia is plesiomorphic. This species appears to be the closest living ancestor of the genus. In subgenus Aristea we continue to recognize three sections, sect. Racemosae, sect. Singulares and sect. Aristea. Nesting of subgenus Pseudaristea within section Racemosae of subgenus Aristea is probably an artefact of the analysis and does not receive bootstrap support, and hence we continue to recognize this group of species at subgeneric rank. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 144, 41–68.

PHYLOGENETIC ANALYSIS OF 32 STRAINS OFVAUCHERIA(XANTHOPHYCEAE) USING THErbcL GENE AND ITS TWO FLANKING SPACER REGIONS1

The completerbcL gene was sequenced for 21 species and 32 strains ofVaucheriaand for five other Xanthophyceae (Asterosiphon dichotomus(Kützing) Rieth,Botrydium becharianumVischer,B. cystosumVischer,B. stoloniferumMitra,Tribonema intermixtumPascher). ThepsbA‐rbcL spacer, upstream of therbcL gene, and the RUBISCO spacer between therbcL andrbcS genes were also completely sequenced for theVaucheriastrains andAsterosiphon.ThepsbA‐rbcL spacer was the most variable region that was sequenced, and only the 3′ end of the spacer could be aligned. Phylogenetic analyses (maximum parsimony, neighbor joining, and maximum likelihood) were conducted using the DNA sequence and the amino acid sequence for therbcL gene, and a second analysis was conducted using a portion of thepsbA‐rbcL spacer +rbcL gene + RUBISCO spacer. All analyses showed thatVaucheriaspecies formed monophyletic clades that corresponded with morphologically based subgeneric sections, including the section Racemosae. Species producing a gametophore (= fruiting branch, bearing both an antheridium and oogonium) formed a monophyletic clade in all analyses. The nongametophore species sometimes formed a monophyletic clade but other times formed a basal grade. Pair‐wise comparisons of nucleotides and amino acids showed that for some species, numerous nucleotide changes resulted in relatively few amino acid changes. Consequently, phylogenetic analysis of the amino acids produced numerous trees, which in a strict consensus tree resulted in numerous polychotomies. An original strain ofV. terrestristhat was deposited in two culture collections over 25 years ago had identical sequences, suggesting no rapid change was occurring in the sequenced regions. Two strains ofV. prona, isolated from Europe and North America, had identical sequences. Other species, for which two or more strains were examined, had different sequences. These results suggest that cryptic species complexes exist withinVaucheriabecause therbcL gene is a conservative gene that is identical in other protists.

Nomenclatural Clarification in Aristea Section Racemosae (Iridaceae) in the Cape Flora of South Africa

We demonstrate that the correct names for three species of section Racemosae of the Afro-Magadagascan genus Aristea are: Aristea capitata (L.) Ker Gawler, A. bracteata Persoon, and A. bakeri Klatt. A neotype is selected for Gladiolus capitatus L. (1753), the basionym of A. capitata (L.) Ker Gawler (1802). Aristea major Andrews (1801) is placed in taxonomic synonymy with A. capitata. The typification and identity of Ixia thyrsiflora D. Delaroche (1766), basionym of Aristea thyrsiflora (D. Delaroche) N. E. Brown (1929), often regarded as conspecific with A. major, remain in question; however, due to priority of publication of the basionyms A. thyrsiflora presents no threat to the stability of A. capitata. Weimarck effectively lectotypified the superfluous and illegitimate name Moraea caerulea Thunberg (1787), basionym of Aristea caerulea (Thunberg) Vahl (1805). Aristea bracteata Persoon (1805) is accepted as a replacement name for M. caerulea, and is the oldest legitimate name available for this species. Aristea monticola Goldblatt (1971) was also published as a replacement name for M. caerulea, and thus falls into synonymy with A. bracteata. Aristea bakeri Klatt (1894) was published as a replacement name for the illegitimate later homonym A. paniculata Baker (1892). Aristea macrocarpa G. J. Lewis (1940) and A. confusa Goldblatt (1970) are placed in taxonomic synonymy with A. bakeri.

New Species of Aristea Section Racemosae (Iridaceae) from the Cape Flora, South Africa

Aristeafimbriata, A. inaequalis, and A. rupicola are new to this genus of some 52 species of sub-Saharan Africa and Madagascar. The new species all occur in the western part of the southern African winter-rainfall climatic zone and are highly local endemics, two of them known only from single extended populations. All three species have threewinged capsules, a specialized condition that defines subgenus Aristea, a taxon virtually restricted to the southern African winter-rainfall zone. In addition the new species have pollen grains with apertures confined to one face of the grain, either monosulcate or trichotomosulcate, and have specialized, undivided styles that define section Racemosae, one of two sections of subgenus Aristea. Observations on the pollination biology of A. inaequalis show that it is probably pollinated by female Anthophora diversipes (Anthophoridae) bees, which forage for pollen on the flowers of this species. This pollination strategy conforms to that of other blueflowered species of the genus, that is, they have flowers adapted for pollination by various species of female bees foraging for pollen. A revised key to section Racemosae is presented, which includes entries for apparently undescribed taxa that require further investigation. Section Racemosae is one of two sections of the exclusively southern African subgenus Aristea of the sub-Saharan African and Malagasy genus Aristea, which comprises some 52 species (Weimarck, 1940; Goldblatt & Manning, 1997; Goldblatt & Le Thomas, 1997). Both section Aristea, with 6 species, and section Racemosae, with an estimated 14 including the 3 new species described here, are largely restricted to the southern African winter-rainfall zone in the south and west of the subcontinent. They also occur almost exclusively on the nutrient-poor, well-drained, rocky sandstone-derived soils that characterize a large part of the winter-rainfall zone. Here we describe three new species of section Racemosae, all narrow endemics of the western half of the winter-rainfall zone. Two of these, Aristeafimbriata and A. rupicola, are comparatively recent discoveries, but A. inaequalis has been known at least since 1911, when it was collected by E. P. Phillips on the Gifberg in northern Western Cape Province. That species has, however, often been confused in herbaria with A. monticola Goldblatt, also called A. caerulea Thunberg, an illegitimate superfluous name (Goldblatt & Barnard, 1970). No specimens ofA. inaequalis were, however, cited under any species of section Racemosae by Weimarck (1940) in the only complete, modemrn account ofArist a, a treatment now seriously out-of-date. All three new species described here have the plesiomorphic pollen grains with a single aperture confined to one surface of the grain and derived, undivid d style branches that characterize section Racemosae (Goldblatt & Le Thomas, 1997), as well as broadly winged capsules with two to four radially compressed seeds per locule that define subgenus Aristea. Aristeafimbriata is distinctive in its low stature, inflorescence with the spathes and bracts fringed and brown-tipped, and, moreover, stands out palynologically in the section in having pollen grains with a trichotomosulcate aperture (Le Thomas et al., 1996; Goldblatt & Le Thomas, 1997). Other species of the section have pollen grains with a conventional elliptic aperture except for one evidently aberrant population of A. zeyheri Baker, which has zonasulculate grains. Plants from other populations have typical monosulcate pollen grains (Goldblatt & Manning, 1997). Aristea inaequalis and A. rupicola are lithophytes and only grow in rock crevices in sandstone outcrops, a habitat that is unusual in the genus. 1. Aristea inaequalis Goldblatt & J. C. Manning, sp. nov. TYPE: South Africa. Western Cape: rocky sandstone plateau at the top of Gifberg, 3 Oct. 1996, Goldblatt & Manning 10561 (holotype, NBG; isotypes, K, MO). Figures 1, 2. Plantae ca. 100-150 cm altae caespitosae, foliis distiNovoN 7: 357-365. 1997. This content downloaded from 157.55.39.177 on Sat, 19 Nov 2016 04:34:40 UTC All use subject to http://about.jstor.org/terms

New Species of Aristea (Iridaceae) from South Africa and Notes on the Taxonomy and Pollination Biology of Section Pseudaristea

Aristea teretifolia and A. cantharophila are new species from the winter-rainfall region of southern Africa. Both belong in section Pseudaristea, one of eight sections of this genus of ca. 52 species of sub-Saharan Africa and Madagascar. Aristea teretifolia has pink, mauve, or cream flowers, the inner tepals of which are longer than the outer and have a large dark blotch near the base, and stands out in the section in its very narrow linear or sometimes terete leaves. Aristea cantharophila has narrow, linear to sword-shaped leaves fairly typical of the section, and mauve or white flowers with subequal tepals, each of which has a zone of dark color near the base. In their long pedicels, oblong-trigonous ovary, large and deeply fringed stigma lobes, and woody, elongate, tardily dehiscent capsules these new species conform closely to the characteristic features of section Pseudaristea. Field observation suggests that both species are adapted for pollination by monkey beetles (Scarabidae: Rutelinae), which use the flowers of these and at least one other species of the section as sites for feeding and mating. The dark markings on the tepals appear to mimic beetles and presumably encourage visits by these insects. The Afro-Madagascan genus Aristea comprises some 52 species (Weimarck, 1940; Goldblatt, 1991, 1995a, b) currently divided among eight sections. As redefined by Goldblatt (1995a), section Pseudaristea Pax comprises five species, all of Western Cape Province, South Africa, a region of winter rainfall and summer drought. To this number we add two new species, A. cantharophila (Fig. 1A) and A. teretifolia (Fig. 1B), and exclude A. zeyheri Baker from the section. The new species are both narrow endemics of lowland sites in the southwestern part of Western Cape Province. They share all the characters that define the section and differ mainly in their unusually colored and marked flowers (Fig. 1), and in the case of A. teretifolia also in its terete or extremely narrow leaves. The defining features of section Pseudaristea are flowers with long pedicels, an oblong and three-lobed to threeangled ovary, large inflorescence spathes concealing the flower buds, prominent and deeply fringed stigma lobes, and woody, elongate, tardily dehiscent, deeply three-lobed capsules. To this list of morphological features can be added di-zonosulculate pollen grains, unique in Iridaceae (Radelescu, 1970; Schulze, 1971; Le Thomas et al., 1996), and exine with reticulate sculpturing. RELATIONSHIPS OF ARISTEA ZEYHERI Aristea zeyheri was assumed by Weimarck (1940) to accord in most of its features with those that define section Pseudaristea. New material collected since Weimarck completed his monograph of the genus in 1940, however, shows that this species has capsules with three prominent, narrow wings, 2-4 flattened, plate-like seeds per locule, and minutely trifid styles. These are exactly the apomorphic features that define section Racemosae. It seems likely that A. zeyheri is most closely related to A. racemosa Baker of that section, which it resembles closely in overall morphology, particularly the slender habit and subterete leaves. The pollen grains ofA. zeyheri are monosulcate, or in one population zonosulculate (unpublished), with rugulose exine. In its exine sculpturing and basic aperture condition, A. zeyheri also accords with section Racemosae, species of which have pollen grains with monosulcate apertures and either microreticulate or rugulose exine (Goldblatt & Le Thomas, in prep.). POLLINATION BIOLOGY OF SECTION PSEUDARISTEA Most species of Aristea have deep blue flowers, bright yellow anthers and pollen, and lack conspicuous dark markings. Preliminary observations on the pollination of the genus indicate that the blueflowered species of Aristea are pollinated by a vaNovoN 7: 137-144. 1997. This content downloaded from 157.55.39.186 on Sun, 09 Oct 2016 04:52:20 UTC All use subject to http://about.jstor.org/terms

Chromosome Numbers and Relationships in Tribe Hemimerideae (Scrophulariaceae)

Chromosome numbers are presented for five genera in the Hemimerideae. Mitotic counts were made for 69 species of Diascia, seven species of Nemesia, six species of Alonsoa, four species of Hemimeris, and two species of Diclis. At the species level, 80 of these counts are new reports. Counts for two genera (Diclis and Hemimeris) are also new. Diascia has a base number of x = 9 and most species are diploid. Four tetraploid and one hexaploid species were discovered among the perennials of section Racemosae, bringing the total number of polyploids for the section to seven of 26 species (ca. 27%). Two species in section Racemosae have more than one cytotype; D. patens has 2n and 4n populations, whereas D. capsularis has 2n, 4n and 6n populations. In section Diascia, consisting entirely of annuals, only five of 46 species (ca. 11%) are tetraploid, while the rest are diploid. Polyploidy has apparently had multiple origins in both sections of Diascia. The seven species of Nemesia counted were uniformly 2n = 18, but hypotheses of a close relationship between Nemesia and Diascia conflict with differences in corolla aestivation and preliminary molecular evidence. Hemimeris and Diclis are diploid with 2n = 14 and appear to be closely related. Alonsoa is also related to Hemimeris with South African species having 2n = 28 and South American species mostly 2n = 56. Chromosomal, pollination and morphological differences between South African and South American species suggest that Alonsoa originated in South Africa and dispersed to South America before or shortly after the breakup of Gondwanaland. If true, the Scrophulariaceae has had a more ancient presence in the Southern Hemisphere than previously suspected.

The Diascia (Scrophulariaceae) window: an orientation cue for oil-collecting bees

The Diascia (Scrophulariaceae) window: an orientation cue for oil-collecting bees. Flowers of Diascia section Racemosae are characterized by an unusual translucent ‘window’ at the base of the upper corolla lip which is bright yellow with maroon flecks and varies from a nearly flat to a deeply cone-shaped depression. The inner epidermal cells of the window are also variable in shape ranging from lenticular to long papillate. In contrast to the surrounding corolla which strongly reflects ultraviolet light, the window tissue is strongly ultraviolet absorptive due to the presence of ultraviolet absorbing flavonoids in the epidermal cells. Observations in natural and experimental situations suggest that the window is used as an orientation cue by oil-collecting bees.

A new species of Diascia (Scrophulariaceae) from the southern Drakensberg

Diascia austromontana K.E. Steiner, section Racemosae , a perennial herb related to D. barberae Hook. f., is described from the southern Drakensberg of Natal and Lesotho. It differs from D. barberae in having spurs one third the length of the corolla limb rather than one half or more, a style that is deflexed rather than reflexed, and a stigma that is ouside the cohering anthers rather than surrounded by them.