Roberto D. Tortosa

A typological analysis of the inflorescences of the genus Nassauvia (Asteraceae)

Summary The inflorescences of the genus Nassauvia are analyzed following Troll’s comparative-morphological approach. Eight types of synflorescences are recognized, each defined by a particular combination of six developmental processes: truncation, proliferation, shortening of internodes, homogenization of paraclades, suppression of paraclades and shortening of peduncles. Decomposing each inflorescence type into six characters, each referring to a hypothesized developmental process, makes the data suitable for cladistic analysis. The synflorescence patterns described in the present analysis mostly correlate with currently accepted infrageneric classifications; discrepancies are discussed. Inflorescences currently described as „pseudocephalia” are shown to be strongly condensed panicles or stachyoids of heads. Sister group inspection suggests the condensed panicle of heads to be the basal inflorescence condition within the genus Nassauvia.

Intermediacy between Grindelia chiloensis and Haplopappus pectinatus (Astereae, Asteraceae)

Intermediate specimens between Grindelia chiloensis and Haplopappus pectinatus occur in Patagonia (Argentina). They were analysed using the methods proposed by Wells (distance diagram) and Wilson (character count procedure). With both methods the hypothesis of hybridity is supported. A close proximity of H. pectinatus to the genus Grindelia is also suggested by a high percentage of stainable pollen grains in the putative hybrids, chromosome morphology, and achene anatomy. Based on such evidence, the new combination G. anethifolia (H. pectinatus Phil., non G. pectinata Baker) is proposed.

A new species of Grindelia (Asteraceae, Astereae) from the Meseta del Somuncura (Patagonia), Argentina

Grindelia coronensis, a new species from the Meseta del Somuncura, Prov. Río Negro, Argentina, is described and illustrated. It is similar toG. chiloensis (Cornel.) Cabrera but it is readily distinguished by its leaves which are conspicuosly differentiated into a obovate blade and a long petiole.

Architecture of the genus Grindelia (Asteraceae: Astereae)

Summary An architectural analysis of the genus Grindelia was carried out, and seven different models were established. Differences in architecture between North American and South American species are pointed out, and their possible taxonomic implications are indicated. The different architectural models are compared with those exhibited by related genera.

Two new species of Grindelia (Astereae, Asteraceae) from Uruguay

Taxonomic revision of South American species ofGrindelia Willd. has revealed two new species from Uruguay:G. rupestris, an erect subshurb with crowded obovate denticulate leaves, subsessile heads, and pappus composed of numerous awns, andG. linearifolia, a prostrate shrublet with small entire linear leaves. Both species are described and illustrated. A key for the UruguayanGrindelia species is provided.

Revision of the North American Species of Grindelia (Asteraceae)1

Abstract A revision of North American species of the genus Grindelia Willd. (Asteraceae) was carried out. Forty-one species, 10 varieties, and two forms are recognized, and a key is given. The following new combinations are made: G. fastigiata Greene var. revoluta (Steyerm.) Adr. Bartoli & Tortosa [≡ G. revoluta Steyerm.], G. hirtella (B. L. Rob. & Greenm.) Adr. Bartoli & Tortosa [≡ G. squarrosa (Pursh) Dunal var. hirtella B. L. Rob. & Greenm.], G. humilis Hook. & Arn. var. platyphylla (Greene) Adr. Bartoli & Tortosa [≡ G. robusta Nutt. var. platyphylla Greene], G. lanceolata Nutt. var. subincisa (Greene) Adr. Bartoli & Tortosa [≡ G. subincisa Greene], G. leptocarpa (De Jong & Beaman) Adr. Bartoli & Tortosa [≡ Olivaea leptocarpa De Jong & Beaman], G. squarrosa f. pseudopinnatifida (D. Löve & J.-P. Bernard) Adr. Bartoli & Tortosa [≡ G. perennis A. Nelson f. pseudopinnatifida D. Löve & J.-P. Bernard], G. squarrosa var. eligulata (Steyerm.) Adr. Bartoli & Tortosa [≡ G. oxylepis Greene var. eligulata Steyerm.], and G. tricuspis (Sch. Bip.) Adr. Bartoli & Tortosa [≡ O. tricuspis Sch. Bip.]. Aster glutinosus Cav. is proposed as lectotype for the genus Demetria Lag. and a neotype is designated for D. spathulata Lag. The following names are lectotypified: G. inuloides Willd., G. lanceolata, G. nana Nutt., G. nana var. integrifolia Nutt., G. platylepis Greene, G. subincisa [≡ G. lanceolata var. subincisa], and G. texana Scheele [≡ G. lanceolata var. texana (Scheele) Shinners]. Seventeen taxa are illustrated for the first time. Resumen Se lleva a cabo una revisión de las especies norteamericanas del género Grindelia Willd. (Asteraceae). Se reconocen 41 especies, 10 variedades y dos formas y se incluye una clave para su determinación. Se realizan las siguientes nuevos combinaciones: G. fastigiata Greene var. revoluta (Steyerm.) Adr. Bartoli & Tortosa [≡ G. revoluta Steyerm.], G. hirtella (B. L. Rob. & Greenm.) Adr. Bartoli & Tortosa [≡ G. squarrosa (Pursh) Dunal var. hirtella B. L. Rob. & Greenm.], G. humilis Hook. & Arn. var. platyphylla (Greene) Adr. Bartoli & Tortosa [≡ G. robusta Nutt. var. platyphylla Greene], G. lanceolata Nutt. var. subincisa (Greene) Adr. Bartoli & Tortosa [≡ G. subincisa Greene], G. leptocarpa (De Jong & Beaman) Adr. Bartoli & Tortosa [≡ Olivaea leptocarpa De Jong & Beaman], G. squarrosa f. pseudopinnatifida (D. Löve & J.-P. Bernard) Adr. Bartoli & Tortosa [≡ G. perennis A. Nelson f. pseudopinnatifida D. Löve & J.-P. Bernard], G. squarrosa var. eligulata (Steyerm.) Adr. Bartoli & Tortosa [≡ G. oxylepis Greene var. eligulata Steyerm.] y G. tricuspis (Sch. Bip.) Adr. Bartoli & Tortosa [≡ O. tricuspis Sch. Bip.]. Se propone Aster glutinosus Cav. como lectotipo del género Demetria Lag. y se designa un neotipo para D. spathulata Lag. Los siguientes nombres son lectotipificados: G. inuloides Willd., G. lanceolata, G. nana Nutt., G. nana var. integrifolia Nutt., G. platylepis Greene, G. subincisa [≡ G. lanceolata var. subincisa] y G. texana Scheele [≡ G. lanceolata var. texana (Scheele) Shinners]. Se ilustran por primera vez 17 taxa.

The New Name Johnstonalia Substitutes for Johnstonia (Rhamnaceae)

ABSTRACT The new name Johnstonalia Tortosa replaces the illegitimate name Johnstonia Tortosa (Rhamnaceae).

A New Species and Variety of Senecio (Asteraceae) from Patagonian Argentina

Abstract Two novelties in the genus Senecio L. sect. Senecio of Patagonia (Argentina) are described and illustrated: a new species, S. breviramulus Tortosa & Adr. Bartoli belonging to series Xerosenecio (Cabrera) Cabrera & S. E. Freire, and the new variety pinohachense Tortosa & Adr. Bartoli for S. volckmannii Phil. belonging to series Suffruticosi Cabrera subser. Candidi (Cabrera) Cabrera & S. E. Freire. The new species is allied to S. covasii Cabrera and S. pumilus Tortosa & Adr. Bartoli, from which it differs by the smaller, narrowly elliptic leaves and narrower heads with fewer flowers. The new variety of S. volckmannii differs from the typical variety by the presence of female ray florets and the pedunculate capitula.

Two new species of Haplopappus (Astereae, Asteraceae) from Mendoza, Argentina

A review of the Argentinean specimens ofHaplopappus Cass. has revealed two new species from Mendoza province, both of the sectionHaplopappus:H. boelkei, unique by its caespitose habit and long petiolate leaves, andH. mendocinus, related toH. macrocephalus (Less.) DC.,H. ochagavianus Phil. andH. tiltilensis Phil.

Analysis of hybridization betweenGrindelia brachystephana andG. chiloensis (Asteraceae: Astereae) in Patagonia, Argentina

Intermediates between two South American species ofGrindelia were found in Chubut Province, Argentina. Twenty eight individual plants with phenotypes ofG. brachystephana, G. chiloensis, or intermediates were collected and studied together with three reference specimens of each of the putative parental species. Discriminant analysis procedure and the computer program HYWIN were applied and results of the two methods are compared. Results demonstrate that most of the specimens collected are of hybrid origin, and that most of the specimens suggested as hybrids are most likely introgressants. Hybridization and introgression are likely the major causes of the high variability previously attributed toG. chiloensis by taxonomists.