Cynanchum laeve |
Apocynaceae |
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bluevine, bluevine milkweed, climbing milkweed, honeyvine, honeyvine milkweed, smooth swallow-wort |
dogbane family, milkweed and dogbane family, milkweed family |
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Habit | Trees, shrubs, lianas, vines, or herbs, perennial, taprooted, rhizomatous, or tuberous; latex milky (clear). | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | puberulent in single line; dwarf axillary branches common (pseudostipules). |
prostrate, trailing, erect, climbing, or twining, indument absent or variously of unicellular or multicellular glandular or eglandular trichomes. |
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Leaves | 1–3 early-caducous stipular colleters on each side of petiole; petiole 1–9 cm, puberulent in single line to glabrate; blade pinnipalmately veined, ovate or deltate, 2–11 × 1.5–10 cm, chartaceous, base shallowly to deeply cordate or sagittate, with 3–8 laminar colleters, margins puberulent-ciliate or glabrate, apex acute, attenuate, acuminate, or apiculate, surfaces minutely puberulent to glabrate on veins. |
deciduous, semipersistent, or persistent, cauline, alternate, opposite, or whorled; stipules absent, stipular colleters variously basal to petiole, interpetiolar, intrapetiolar, or absent; petiole present or absent; blade margins entire, venation pinnate, pinnipalmate, or a single vein, laminar colleters borne at adaxial base or absent. |
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Inflorescences | racemiform to paniculiform, solitary (paired) at nodes, 6–30-flowered; peduncle 0.2–2(–6.5) cm, puberulent in single line; bracts caducous, 1, at base of each pedicel. |
extra-axillary, axillary, terminal, or pseudoterminal, cymose, often racemiform, umbelliform, corymbiform, or paniculiform, pedunculate (sessile). |
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Pedicels | 3–12 mm, tomentulose. |
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Flowers | calyx lobes erect, lanceolate to ovate, 1.5–2 mm, apex obtuse, acute, or acuminate, puberulent to glabrate, margins ciliate to glabrate; corolla cream, campanulate, tube 1–1.5 mm, lobes erect to spreading, plane to somewhat twisted, linear-lanceolate, 3.5–6 mm, glabrous, inframarginal adaxial ridges absent; corona united to column near base, composed of 5 distinct segments, cream, laminar, slightly exserted from corolla, ovate with apex deeply divided into 2 subulate, usually twisted lobes, 4–6 mm; style apex conic. |
perianth and androecium hypogynous [perigynous, epigynous]; sepals 5, connate, calycine colleters absent or present; petals 5, connate, corolla rotate, rotate-reflexed, campanulate, funnelform, urceolate, tubular, or salverform, aestivation dextrorse, sinistrorse, or valvate; corolline corona absent, annular, or of 5 scales or pads; stamens 5, antisepalous, epipetalous, sometimes connate throughout; anthers 2-thecous, free, connivent, or adnate to gynoecium and forming a gynostegium, margins with corneous wing in species with a gynostegium, 2- or 4-locular; gynostegial corona absent or of 5 separate or united scales, filaments, cups, or other diverse forms; pollen in monads, tetrads, or massed in each theca into a rigid pollinium, translators absent or present, when present, receiving tetrads of adjacent anthers (Cryptostegia) or joining pollinia of adjacent anthers to a common corpusculum, together forming a pollinarium; pistils 1, 2-carpellate, connate only by style apices; ovaries superior [partly inferior], 1-locular; styles 1 or 2, apical; stigmas subapical or lateral; ovules few–numerous; nectaries variously around the base of ovaries, on gynostegium, on receptacle, or absent. |
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Fruits | follicles, capsules, berries, or drupes, solitary or paired, erect or pendulous, striate, spiny, winged, or smooth. |
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Seeds | 50–100, tan to light brown, 8–10 × 5–7 mm, thickly winged, chalazal margin erose, faces minutely foveolate; coma white to tawny, 3–4 cm. |
few–numerous, brown or black, flattened, navicular, or cylindric, marginally winged or not, comose or not, arillate or not. |
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Latex | clear. |
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Follicles | ovoid to lance-ovoid, straight to falcate, 7–15 × 2–3.5 cm, apex attenuate, thick-walled. |
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2n | = 22. |
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Cynanchum laeve |
Apocynaceae |
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Phenology | Flowering Apr–Nov; fruiting Jul–Dec. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Streamsides, flood plains, canyons, dunes, roadsides, fields, gardens, cities and towns, especially on fences, riparian woods, thickets, deciduous forest, prairies. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 0–700 m. (0–2300 ft.) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
AL; AR; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MD; MI; MN; MO; MS; NC; NE; NJ; NY; OH; OK; PA; SC; TN; TX; VA; WV
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nearly worldwide; especially in tropics and subtropics |
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Discussion | Cynanchum laeve is a common and fairly weedy species from valleys west of the Appalachians to the central Great Plains. It is especially common in valleys of tributaries to the Mississippi River. It is far more evident as a weed on fences along roads, in fields, and in urban lots and gardens than in less-disturbed vegetation. Prior to massive anthropogenic environmental change in North America, the natural habitat was likely riparian vegetation. The deeply seated rhizomes are difficult to remove, and the vine is hard to eradicate from managed landscapes, where they are not necessarily unwelcome guests. The flowers are sweetly fragrant, hence the common name honeyvine. Cynanchum laeve has been reported from Ontario, but the author has not seen specimens to confirm its presence in the province. A report from Idaho is based on a misidentified specimen of Metaplexis japonica (Thunberg) Makino. Occurrences on the western and northern margins of the range and east of the Appalachians likely represent recent range expansion. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera ca. 460, species ca. 4800 (36 genera, 175 species in the flora). From the early nineteenth into the latter half of the twentieth centuries, the pollinia- and gynostegium-bearing species were segregated as the family Asclepiadaceae Borkhausen. The structure of the combined androecium and gynoecium and their function in pollination are the most complex among eudicots (P. K. Endress 1994). Ample morphological and molecular phylogenetic evidence provided a sound basis for reuniting these families (M. E. Fallen 1986; H.-E. Wanntorp 1988; B. Sennblad and B. Bremer 1996). As yet, the sister group of Apocynaceae within Gentianales is uncertain, with some analyses indicating Gelsemiaceae and others Gentianaceae (P. F. Stevens 2001 onwards, http://www.mobot.org/MOBOT/research/APweb/). The current classification of Apocynaceae allocates genera to five subfamilies and further into tribes and, in some cases, subtribes (M. E. Endress et al. 2014). Three subfamilies that composed the former Asclepiadaceae (Asclepiadoideae Burnett, Periplocoideae R. Brown ex Endlicher, Secamonoideae Endlicher) have been repeatedly demonstrated to be monophyletic, whereas both of the remaining two subfamilies that composed Apocynaceae in the narrow sense (Apocynoideae Burnett, Rauvolfioideae Kosteletzky) are clearly paraphyletic (T. Livshultz et al. 2007). We follow the current classification here, recognizing that future revisions will be required to obtain monophyletic higher taxa. Genera of Rauvolfioideae (nos. 1–13), Apocynoideae (nos. 14–23), Periplocoideae (no. 24), and Asclepiadoideae (nos. 25–36) are present in the flora area. Apocynaceae species possess diverse secondary compounds, some of which are potent toxins or are pharmacologically active. The indole alkaloids vincristine and vinblastine present in Catharanthus roseus are used in the treatment of Hodgkin’s lymphoma, leukemias, and other cancers. Toxic cardiac glycosides in Asclepias are sequestered by several species of milkweed-feeding insects for use in their own defense, most famously by the monarch butterfly (S. B. Malcolm 1991). Species of Vinca have long been cultivated as evergreen ground covers with showy flowers; species of Amsonia and Asclepias are also widely cultivated, especially for the nectar-rich flowers that are attractive to butterflies and other insects. Cultivated Vinca and Vincetoxicum species readily naturalize, are considered invasive, and present serious management concerns. The following species have been reported as naturalized or escaped from cultivation, but are excluded from this treatment because convincing proof of persisting populations is lacking: Calotropis gigantea (Linnaeus) W. T. Aiton, C. procera (Aiton) W. T. Aiton, Gomphocarpus fruticosus (Linnaeus) W. T. Aiton, G. physocarpus E. Meyer, Metaplexis japonica (Thunberg) Makino, Periploca graeca Linnaeus, and Vincetoxicum hirundinaria Medikus. Calotropis gigantea and C. procera are infrequently cultivated in California and Florida. Two collections of C. procera are known outside of cultivation. In California, the species was collected in an agricultural area in Imperial Valley (Laemmlen s.n., UCR-51373). The single individual was destroyed with no subsequent sign of naturalization in the area (A. C. Sanders, pers. comm.). In Florida, collections have been made from a soil dump (suspected to be from the Bahamas) in Hillsborough County in which numerous exotic species appeared (A. R. Franck, pers. comm.; Dickman s.n., USF-273524). Gomphocarpus fruticosus [Asclepias fruticosa Linnaeus] and, especially, G. physocarpus [A. physocarpa (E. Meyer) Schlechter] have been cultivated in the flora region; the popularity of G. physocarpus appears to have increased dramatically in recent years because of its rapid growth and the novelty of the inflated, soft-spined follicles. Neither species is winter hardy in most of our region, although they may persist for a few years as far north as USDA Plant Hardiness Zone 7. Nonetheless, these species have not been documented often by herbarium specimens from the region, and in nearly all cases it is certain that they represent cultivated plants. A recent collection of G. physocarpus made in Ventura County, California, in 2016 (Provance 1116-02, UCR-278890) may represent the beginning of an established population. Botanists in California, Florida, and Texas should be cognizant of the possibility that these species may establish here, as they have in subtropical regions around the world. Metaplexis japonica [Cynanchum rostellatum (Turcz.) Liede & Khanum] was reported from an Iowa State University agricultural research farm in the late 1950s and early 1960s (S. L. Welsh and D. E. Anderson 1962). It was suggested that the species may have been introduced during World War II through investigations of fiber sources. Eradication measures were undertaken, and there is no evidence from collections—or observations (D. A. Lewis, pers. comm.)—that the species persists in the state. An additional collection of the species was made in Canyon County, Idaho, in 1966 (Linford s.n., ID-106861). However, no additional collections have been made since, and western botanists report being unaware of any populations of the species in the state at this time (B. Ertter, pers. comm.; J. Smith, pers. comm.). Until the end of the last century, Periploca graeca was cultivated as an ornamental subject across the warmer parts of the flora region. It seems to have fallen out of favor in recent times. There are several collections housed at herbaria, all of which pertain to cultivated plants or plants persisting for years to perhaps decades around homesteads. However, P. graeca does not appear to be naturalized anywhere in our region. Vincetoxicum hirundinaria [synonyms: Cynanchum medium (Decaisne) K. Schumann, not R. Brown, C. vincetoxicum (Linnaeus) Persoon, V. medium Decaisne, V. officinale Moench] has been rarely cultivated in the region but is widely reported as a member of regional floras. Reports of naturalized populations ascribed to V. hirundinaria (or one of its synonyms) pertain to V. rossicum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 14. | FNA vol. 14. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Apocynaceae > Cynanchum | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Synonyms | Gonolobus laevis, Ampelamus albidus, A. laevis | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | (Michaux) Persoon: Syn. Pl. 1: 274. (1805) | Jussieu | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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