Topic
Aristea
About: Aristea is a research topic. Over the lifetime, 18 publications have been published within this topic receiving 190 citations.
Papers
TL;DR: Two new species from the winter-rainfall region of southern Africa are added, A. teretifolia and A. zeyheri, which conform closely to the characteristic features of section Pseudaristea, one of eight sections of this genus of sub-Saharan Africa and Madagascar.
Abstract: 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
11 citations
TL;DR: Three new species of Aristeafimbriata, A. inaequalis, and A. rupicola are new to this genus of some 52 species of sub-Saharan Africa and Madagascar, and are highly local endemics of the western part of the southern African winter-rainfall climatic zone.
Abstract: 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
7 citations
6 citations
1 Jan 2000
TL;DR: Phylogenetic analyses clarify the evolution of pollen morphology and its systematic significance in Iridaceae and find the microreticulate, monosulcate type found in Geosiris also resembles the basic type in African Aristea, consistent with its suggested position near the base of the subfamily.
Abstract: Phylogenetic analyses clarify the evolution of pollen morphology and its systematic significance in Iridaceae. According to the classification of Goldblatt (1991), the subfamily Nivenioideae consists of six genera: Nivenia (9 spp.), Klattia (3 spp.) and Witsenia (1 sp.) in the southwestern Cape (South Africa), Aristea (ca. 50 spp.) in Africa and Madagascar, Patersonia (ca. 20 spp.) in Australia, and Geosiris (1 sp.), a saprophyte endemic to Madagascar. The first three genera form a monophyletic group with monosulcate pollen and reticulate sculpturing, as in the basal genus Isophysis, which forms its own subfamily. Pollen of Aristea is highly diverse, with plesiomorphic monosulcate types and derived dizonasulculate, trisulcate to spiraperturate and sulculate types, which correspond to three large clades within the genus. The microreticulate, monosulcate type found in Geosiris also resembles the basic type in African Aristea, consistent with its suggested position near the base of the subfamily. The genus Patersonia is unique among Nivenioideae in having inaperturate pollen convergent with that of certain Ixioideae and Iridoideae (Diplarrhena).
4 citations
Journal Article•
TL;DR: A peculiar tephritid from Mt. Kenya and its affinities within the Sphenella group of genera are discussed and a key to the included genera provided.
Abstract: A peculiar tephritid, Orthocanthoides aristae, new genus and species, is descriptionbed from Mt. Kenya and its affinities within the Sphenella group of genera are discussed. The Sphenella group is redefined, and a key to the included genera provided.
3 citations
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| Year | Papers |
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| 2015 | 1 |
| 2013 | 2 |
| 2008 | 1 |
| 2007 | 1 |
| 2005 | 1 |
| 2004 | 1 |