Donald J. Pinkava

Chromosome Numbers in Some Cacti of Western North America-II

Documented chromosome numbers and meiotic behavior were recorded for 23 taxa of 18 species of Cactaceae of south-western United States and adjacent Mexico. All taxa are diploid (n = 11) or polyploid (n = 22, 33, 44), and with regular meiotic behavior.

A Cytological and Morphometric Analysis of a Triploid Apomict, Opuntia xKelvinensis (Subgenus Cylindropuntia, Cactaceae)

A morphometric analysis ofOpuntia spinosior, O. fulgida, and their putative hybrid,O. × kelvinensis was supplemented with cytogenetic data and pollen stainability for all OTUs. The morphometric analysis supported the hypothesis for the hybrid origin ofO.×kelvinensis and indicated that limited backcrossing has occurred betweenO.×kelvinensis andO. spinosior. Almost all individuals investigated ofO.×kelvinensis are triploid, with 33 chromosomes, those ofOpuntia fulgida are mostly diploid, but in part triploid, and all ofO. spinosior investigated are diploid. The very high percentage of sterile seed produced by triploidO.×kelvinensis is almost certainly a consequence of unequal segregation of chromosomes in pollen mother cells during anaphase I. The ability ofO.×kelvinensis to reproduce vegetatively is attributable to itsO. fulgida parentage. It is hypothesized that the success ofO.×kelvinensis is a result of its particularly preadaptive genome isolated from infrequent backcrossing via meiotic irregularities of odd-polyploidy and its ability to reproduce vegetatively.

Chromosome numbers in some cacti of western North America-VIII.

Abstract: Chromosome numbers are determined for 514 individuals belonging to 119 taxa within Cactaceae. Nineteen taxa have chromosome numbers reported for the first time. Based on geographic, morphological, and cytological data, three new nomenclatural combinations are made: Cylindropuntia ×cardenche (GRIFFITHS) PINKAVA & M. A. BAKER, Cylindropuntia imbricata (HAWORTH) F.M.KNUTH var spinitecta (GRIFFITHS) M.A.BAKER, and Echinocereus bonkerae THORNBER & BONKER ssp apachensis (W.BLUM & RUTOW) A.D.ZIMMERMAN. Four species are here newly published as interspecific hybrids based, in part, on several character states intermediate of their respective sympatric putative parents: Cylindropuntia ×cardenche (GRIFFITHS) PINKAVA & M.A.BAKER (pro. sp) comb. nov., Cylindropuntia ×pallida (ROSE) F.M.KNUTH (pro. sp), Opuntia ×charlestonensis CLOKEY (pro. sp), and Opuntia streptacantha LEMAIRE × O. tomentosa SALM-DYCK.

Miscellaneous Chromosome Numbers in Opuntieae Dc. (Cactaceae) with a Compilation of Counts for the Group

Abstract: Chromosome counts of members of the Opuntieae were carried out to further our understanding of ploidal levels, species boundaries, and evolutionary patterns within this group of stem succulents, which has been well-studied cytologically and is well known for hybridization and polyploidy. Here we counted chromosomes of 53 taxa in 4 genera (Consolea Lem., Nopalea Salm-Dyck, Opuntia Mill., and Tacinga Britton & Rose). Thirty of these counts are the first for a given taxon, and six counts represent a different ploidy for a taxon than has been reported previously. We also present a review of chromosome counts reported for Opuntieae. Ploidy in these taxa ranged from diploid, 2n = 2x = 22, to 20-ploid, 2n = 20x = 220. Of the 164 species in the Opuntieae for which chromosome counts have been carried out, including our new counts, 26.2% are diploid, 13.4% are both diploid and polyploid, and 60.4% are polyploid reiterating that the frequency of genome duplication in the group is far more common than diploidy.

A new species of Mimosa (Leguminosae) from Coahuila, Mexico

Mimosaunipinnata from the Sierra de San Marcos in the Cuatro Ciénegas Basin of central Coahuila, Mexico, is described. It is unique among mimosas in having oncepinnate leaves.

Biosystematic study of Berlandiera (Compositae)

Berlandiera is revised to includeB. subacaulis, B. pumila, B. texana, andB. lyrata with its varietieslyrata andmacrophylla. All species may be induced to interbreed readily, producing F1 progeny which are vigorous but with reduced fertility. Sympatric species produce natural hybrids which are proposed here asB. Xhumilis (=B. pumila XB. subacaulis) andB. Xbetonicifolia (=B. pumila XB. texana). All taxa investigated hadn = 15 chromosomes, including new counts forB. subacaulis and all six F1 hybrids.

Cirsium coahuilense (Asteraceae), a new species from northern Mexico.

Cirsium coahuilense G. Ownb. & Pinkava occurs naturally in the desert areas of Coahuila, Mexico. Morphologically, the new species is most closely allied to C. excelsius (Robins.) Petrak from San Luis Potosi. The first collections of this new species seen by the writers were made by S. S. White at Monclova and later at Cuatro Cienegas, Coahuila, in 1939. E. G. Marsh also collected it at Cuatro Cienegas later in the same year. More recent collecting, principally by botanists associated with the Chihuahuan Desert Flora project, have made available abundant and representative material from which the following diagnosis is drawn: Cirsium coahuilense G. Ownb. & Pinkava, sp. nov. Herba canescens biennis vel perennis; caulis 0.5-3.0 m altus radice palari; folia subtus tomentosa supra tomentosa ad glabrata sed non his- pida, margine infirme aceulato vel ubi dentato quoque dente spina 1.0- 3.5 mm longa terminato; folia caulina principalia infirme ad valde lobata prorsus decurrentia alis prominentibus; folia caulina supera elliptica ad lanceolata, integra ad infirme lobata, summa ad bracteas aciculares re- ducta; ramuli ultimi minute bracteati, quoque ramulo capitulum erectum pedunculatum terminale et interdum subtus in axillis bractearum capit- ula subsidiaria plerumque abortiva subtus ferente; involucrum sub an- thesi 1.2-1.4 cm latum, 1.7-2.0 cm altum; phyllaria in 5-6 seriebus valde imbricata tomentulosa marginibus arachnosis linea mediale glutinosa, spina terminale acute divergente 1.8-3.2 mm longa; phyllaria interioria anguste elongata innocua; corolla dilute lavendula 18-23 mm longa, tuba 7-10 mm longa, limbo 11-14 mm longo, lobis anticis 6-8 mm longis; apices antherarum 0.6-0.8 mm long, attentuati; rami styli 3.4-4.6 mm longi; pappus albus ad alutaceus setis 14-18 mm longis; achenia alutacea vel parum olivacea, praeter labrum stramineum concolora, 1.4-1.8 mm lata, 3.5-5.0 mm longa. Very leafy, canescent biennial or short-lived perennial; stem 0.5-3.0 m tall, arising from a tap root, widely and diffusely branched at the middle and upward, tomentulose at first, glabrate in age, not at all hispid, very leafy along the main axis and bases of the branches, the extremities of the branches nearly naked (except in depauperate plants) due to re- duction of leaves to bracts; all the leaves tomentose below, tomentose,