Cirsium Species Research Articles

HOST RANGE OF LEMA CYANELLA (COLEOPTERA: CHRYSOMELIDAE), A CANDIDATE FOR BIOCONTROL OF CANADA THISTLE, AND OF FOUR STENOPHAGOUS, FOREIGN THISTLE INSECTS IN NORTH AMERICA

AbstractIn the field in Europe, Lenta cyanella (L.) has been reported to breed only on Canada thistle (Cirsium arvense (L.) Scop.) whereas in the laboratory it breeds on species in the genera Cirsium, Carduus, and Silybum. In one laboratory choice test, L. cyanella preferred Cirsium drummondii T.&G. over Canada thistle. In one field-cage test, it concentrated feeding and oviposition on one C. drummondii which thrived in preference to three other C. drummondii and Canada thistle which grew poorly. In a second field-cage test, Canada thistle predominated and L. cyanella fed and oviposited most on Canada thistle although its intrinsic preference for C. drummondii was still apparent. A review of the field host-plants of three accidentally introduced thistle-feeding insects, Orellia ruficauda (F.), Cleonus piger Scop, and Cassida rubiginosa Müller, and the introduced biocontrol agent Rhinocyllus conicus Froel., showed that these insects, which have a wider range of hosts than has L. cyanella, concentrate breeding on introduced species of Cynareae (Compositae). Based on this evidence, it is extrapolated that L. cyanella will exploit Canada thistle and will not damage populations of native Cirsium species when established in North America.

Bracteal Exudates in Two Cirsium Species as Possible Deterrents to Insect Consumers of Seeds

Bracteal Exudates in Two Cirsium Species as Possible Deterrents to Insect Consumers of Seeds

Further tests on Ceutorhynchus trimaculatus F. as a candidate for the biological control of Carduus thistles

Tests were conducted on Ceutorhynchus trimaculatus F. (Coleoptera: Curculionidae), a candidate for introduction from Europe into North America, for the biological control of Carduus thistles which are major weeds in pastures, rangeland and interstate highway embankments. Host specificity tests conducted simultaneously in Blacksburg, Virginia and in Albany, California were to determine whether Cirsium species native to the USA, and considered to be endangered species, are acceptable as hosts to the weevil, and if there is any preference for the Cirsium over the Carduus thistle species. In Virginia, three Cirsium species were compared with Carduus thoermeri Weinmann (musk thistle) and, in California, four Cirsium species were compared with Carduus macrocephalus L. Adult weevils fed on all test species, to a greater extent on musk thistle than on the Cirsium spp. except for Cirsium discolor (Muhl.) Spreng. which was preferred to musk thistle. Cirsium arvense (L.) Scop., Cirsium discolor and musk thistle supported oogenesis of Ceutorhynchus trimaculatus, but the greatest number of eggs was in musk thistle. Ovipositional preference was also shown for musk thistle over the Cirsium spp. in comparison tests using leaf bouquets, although no distinct preference for oviposition on rosettes was found. Besides musk thistle, both Cirsium occidentale (Nutt.) Jepson and Cirsium brevistylum Cronq. supported development from first instar to the adult stage. These results indicate that several of the Cirsium species tested are acceptable as hosts of Ceutorhynchus trimaculatus under caged conditions. However, musk thistle was preferred for feeding, oogenesis and oviposition.

A study of four species of Cirsium native to Mexico

A study of four species of Cirsium native to Mexico

Periodicity of Seedling Emergence and Achene Survival in Some Species of Carduus, Cirsium and Onopordum

(1) Achenes of seven species of Carduus, Cirsium and Onopordum were collected in August-September and mixed with the top 2-5 or 7-5 cm of soil which was then periodically disturbed during 3 or more years. (2) Between 0 and 40% of the achenes produced seedlings in the autumn of sowing. There was wide variation between sowings of the same species in different years, as well as between species. (3) Subsequent seedling emergence was mainly in March-April (Cirsium eriophorum, C. palustre, C. vulgare), April (Carduus acanthoides, C. nutans) or April-May (Cirsium arvense). Onopordum acanthium showed a contrasting pattern; most seedlings appeared in July-September, with small numbers in other months. (4) More than 90% of all seedlings of Cirsium and Carduus spp. that emerged did so within a year after sowing. There were few or none after the second year and very few dormant achenes remained after 5 years. (5) Only about half the achenes of 0. acanthium mixed with 7-5 cm of soil produced seedlings in the first 16 months. Seedlings continued to appear subsequently and up to 8%. of the achenes sown were still dormant and viable after 5 years.

Evolution of male sterility mechanisms in gynodioecious and dioecious species ofCirsium (Cynareae, Compositae)

The genusCirsium comprises both gynodioecious and dioecious species. The observation of microsporogenesis in female plants ofC. montanum, C. oleraceum, C. palustre andC. spinosissimum shows that the male sterility is due to a degeneration of the tapetum. This degeneration occurs more or less early according to the species and, in the light of these results, a scheme of evolution in the male sterility mechanism is proposed. Furthermore, the male sterility mechanism inC. montanum is very similar to that previously found in female plants of the dioecious speciesC. arvense. This fact enhances the possibility of evolution of the dioecy ofC. arvense from the gynodioecy found in other species. According to these results, a general scheme of evolution of sexes in the genusCirsium is proposed.

The Cirsium arizonicum complex of the southwestern United States

The morphology, cytology, distribution, and phylogeny of eight species of the southwestern United States closely related to Cirsium arizonicum are considered. These species form a natural group distinguished from other North American species of Cirsium by a short stigma (1–3 mm) and long corolla lobes (10–20 mm) which are longer than the corolla throat. Three new species described are C. chellyense, C. chuskaense, and C. navajoense. Original chromosome counts are presented for C. nidulum, 2n = 34; C. rothrockii, 2n = 30; C. arizonicum, n = 15; C. chuskaense, 2n = 34; and C. arizonicum × nidulum, 2n = 32, 34.

Two new flavone glycosides from Cirsium lineare

An examination of four species of Cirsium disclosed the presence of two new flavonoids in C. lineare. The structure of one was 5,4′-dihydroxy-6,7,3′-trimethoxyflavone (cirsilineol) 4′-monoglucoside and the other 5,3′,4′-trihydroxy-6,7-dimethoxyflavone (cirsiliol) 4′-monoglucoside. Luteolin 7-glucoside was found in C. suffultum, and pectolinarin and linarin in C. kamtschaticum and C. pectinellum.

Cirsimaritin-4′- O-rutinoside, a new flavone glycoside from Cirsium brevistylum

An examination of five species of Cirsium disclosed the presence of a new flavone glycoside in C. brevistylum. The structure of the compound was established as cirsimaritin-4′- O-rutinoside(4′-rutinosyloxy-5-hydroxy-6,7-dimethoxyflavone). The compound was not present in C. edule, C. undulatum, C. vulgare, or C. arvense.

Cytotaxonomy of some Cirsium species of the eastern United States, with a key to eastern species

The morphology and chromosome number of nine species of Cirsium of eastern North America are considered. Chromosome counts are presented for the first time for C. iowense, 2n = 18; C. lecontei, 2n = 32; C. nuttallii, 2n = 24, 28; C. repandum, 2n = 30; C. smallii, 2n = 34; C. engelmannii, 2n = 20; C. texanum, 2n = 22, 24; C. virginianum, 2n = 28. Additional chromosomes, possibly to be considered as accessories, were found in C. nuttallii, C. engelmannii, and C. texanum. These chromosomes render uncertain the number characteristic of these species. A key to the 26 native and introduced species found in Canada and the United States east of 100° west latitude is presented. The interrelationships of the eastern species and of the species of the western series Undulata are discussed.

THE CHROMOSOME NUMBER OF GALACTITES DURIAEI SPACH (COMP.)

In a previous paper (Gadella c.s. 1966) a list of chromosome numbers of flowering plants of S. France and Spain was published. Unfortunately, one of the plants was misidentified. Collection number 61, collected near Javea, Monte Mongo, Alicante (Spain), was incorrectly assigned to Cirsium acarna (L.) Moench. The plant was considered to be a Cirsium in view of the plumose pappus. The chromosome number of a number of plants grown from this seedsample turned out to be 2n = 22, a number not found earlier in any Eurasiatic species of Cirsium. Moore & Frankton (1963) studied several North American species of the genus Cirsium and pointed out that in the North American representatives of Cirsium the chromosome numbers 2n = 34, 32, 30, 28, 26, 24, 22, 20, 18 were present, whereas the Eurasiatic species exclusively show multiples of n = 17.

CYTOTAXONOMY OF FOLIOSE THISTLES (CIRSIUM SPP. AFF. C. FOLIOSUM) OF WESTERN NORTH AMERICA

Four related Cirsium species of western North America are considered with respect to morphology, cytology and distribution: Cirsium acaulescens (2n = 34), C. congdonii (2n = 34), C. coloradense, and C. scariosum (2n = 34). A new Californian species, C. congdonii R. J. Moore & C. Frankton, is described. Phylogeny of these and other related species is discussed.

HOST SPECIFICITY OF ALTICA CARDUORUM GUER. (COLEOPTERA: CHRYSOMELIDAE)

The flea beetle Altica carduorum Guer. could be reared only on plants of the closely related genera Cirsium, Silybum, and Carduus. The relative acceptability of the different species within this group was correlated with the closeness of their taxonomic relationships to Cirsium arvense (L.) Scop. It is concluded that, in the field, the beetle will be restricted to attacking a few species of Cirsium and will not endanger any economic plant in North America. Thus it is a suitable insect to be used for the biological control of C. arvense in North America. Results of preliminary liberations of A. carduorum are insufficient to indicate if it will exert effective control of the weed in Canada.

Ricerche Cito-Embriologiche E Distribuzione Geografica diCirsium CasabonaeLam. ET DC.(Compositae)

Abstract Cyto-embryological study and geographical distribution of CIRSIUM CASABONAE Lam. et DC. — The mature megagametophyte of Cirsium Casabonae Lam. et DC. (Compositae) is eight nucleate of the normal or Polygonum type. In the nucellus there is only one megaspore mother cell. After meiosis the three micropylar megaspores degenerate. The three antipodal cells start to degenerate as soon as the gametophyte reaches maturity. Microsporogenesis is regular. The chromosome number of Cirsium Casabonae Lam. et DC. is 2n = 32. This shows that also in Europe, as in America, there is at least one species of Cirsium with basis number × = 16. The study of the geographical distribution of Cirsium Casabonae Lam. et DC. shows it to be an Atlantic-West Mediterranean endemism.

CYTOTAXONOMY, PHYLOGENY, AND CANADIAN DISTRIBUTION OF CIRSIUM UNDULATUM AND CIRSIUM FLODMANII

The morphology and specific differences of Cirsium undulatum (Nutt.) Spreng. and of C. flodmanii (Rydb.) Arthur are described and their Canadian distributions are reported in detail. The chromosome numbers are C. undulatum f. undulatum and f. album Farwell, 2n = 26; C. flodmanii f. flodmanii and f. albiflorum D. Löve, 2n = 22. The origin of four North American species of Cirsium that do not follow the world-wide base number 17 is discussed; it is postulated that reduction in number has occurred by translocations. The chromosomes of species with reduced numbers are larger than those of the unreduced species but the total length of the chromosomes of both groups is approximately the same.

On the Correct Names of three European Species ofCirsium

On the Correct Names of three European Species ofCirsium

Morphological and Anatomical Studies of the Vegetative Organs of Rhexia

Considered from an anatomical point of view, these two species may be distinguished from each other by the following contrasting characters: R. virginica.-Roots tuberous where the shoots develop; no stereids outside the leptome of the root; stem broadly four-winged, with three mestome strands in each wing; one central mestome strand in the pith; no cuticular striations above ventral epidermis of leaf; stomata only on dorsal face; midrib with a supernumerary mestome strand; clavate glandular hairs on dorsal face of leaf. R. mariana.-Roots slender throughout; stereids outside the leptome of the root; stem narrowly four-winged, with one mestome strand in each wing; no central mestome strand in the pith; cuticular striations very distinct above ventral epidermis of leaf; stomata on both faces of leaf; midrib without a supernumerary mestome strand; clavate glandular hairs on both faces of leaf. Common to both species are the bicollateral mestome bundles of stem and leaf; the absence of specialized subsidiary cells around the stomata; the absence of mechanical tissues (stereome and collenchyma); the occurrence of two types of glandular hairs; the bifacial structure of the leaves; and the ability of the roots to produce shoots. Vegetative propagation, therefore, depends upon the development of root-shoots, and, upon examining herbarium material, the same mode of propagation was found in R. lutea Walt., in which the roots are very long and slender, and the base of the shoot may persist for more than one season, R. lanceolata Walt., R. serrulata Nutt., and R. ciliosa Michx. All agree with R. mariana in the roots being slender and able to produce shoots. In R. serrulata one specimen appeared as if it was a seedling and blooming in the first season; and one specimen of R. floridana Nash had a tuberous root in addition to the slender, shoot-bearing root. I believe that Rhexia must be placed with that type of plants in which the production of root-shoots is necessary to the normal development of the individual. It is a type poor in representatives, and Wittrock enumerates species of Cirsium, Linaria, Convolvulus, Thesium, Coronilla, Epilobium, and Euphorbia as representing it. Thladiantha dubia Bge. doubtless belongs to this same category, according to Sachs, who states that "the yearly regeneration is dependent upon root-shoots which develop from tuberous swellings of the very long and slender roots." The internal structure of the roots of this curcurbitaceous plant is described by Scott and Brebner, but is very different from that observed in Rhexia.