Common Name: variable flatsedge. Family Name: Cuscutaceae Species Code: CYDI Native Range: Southern Europe, Africa, Asia, and. Whole plants, Roots fibrous; tubers dark brown to black, irregularly shaped, cm long when fully grown. Each tuber has an apical bud and several lateral buds . Plants also recover quickly after fire and can tolerate at least several weeks of deep flooding (Cook et al., ). Currently, C. dactylon is listed.
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This species is a C 4 grass included in the Global Compendium of Weeds. It is a fast-growing grass that spreads by seeds and stolons and rapidly colonizes new areas and grows forming dense mats. After dormancy, it cperus the ability klasifikaai easily re-sprout from stolons and rooted runners. Plants also recover quickly after fire and can tolerate at least several weeks of deep flooding Cook et al.
The name Cynodon dactylon is universally accepted for this common, widespread weed.
It is highly variable and various subspecies have been distinguished Harlan et al. A few klasifiiasi related species can also occur as weeds in some regions see Similarities with Other Species. Although it is not native to Bermuda, C. It is presumed to have arrived in North America from Bermuda, resulting in its common name of Bermuda grass.
The runners spread horizontally and bear nodes with internodes of about 10 cm length. They may be flattened or cylindrical, mostly unhaired. Each node roots in the soil and produces short culms cyperysup to 25 cm high, but develop into prostrate runners under less dense conditions. The almost unique character of the Cynodon genus of at least two and often three leaves at each node can be seen on the extended runners.
This immediately distinguishes it from other perennial weeds with comparable growth pattern such as Panicum repen s and Paspalum distichum Perez and Labrada, The rhizomes are mainly in the top 10 cm of the soil but may penetrate to a rotundue of 35 cm Perez and Labrada, ; Phillips and Moaisi, They may be twice as wide as the runners and this is one of the variable characters in populations 0.
Cypeerus node is covered by a white cataphyl. Runner or rhizome nodes may bear up to three viable buds. Leaves have an alternate-distal pattern of distribution along the runners. Leaf blades are open up to the base, unhaired, similar or shorter than the length of the internode. The ligule is very short but with a conspicuous fringe of white hairs. The width and pilosity of the weed blade may be used to distinguish populations of the weed Oakley, The inflorescence is supported on a culm up to 25 cm high and consists of a single whorl of narrow racemes, each cm long.
Glumes are one-nerved, the lower almost as long as the spikelet, the upper half to three-quarters as long. The lemma is silky pubescent on the keel, palea glabrous. Caryopses are sub-eliptical, compressed and brownish, brilliant coloured Kissmann, The seedling has a hairy ligule, bearing 0.
Pilosity increases as the seedling grows. It also spreads into temperate areas of Europe and North America but is limited by sensitivity to prolonged frost.
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Klasifikazi Table Details section which can be selected by going to Generate Report. The date of the initial introduction of C.
Ecophysiological and genetic traits coupled with both forms of propagation give this species a high score for success in almost any ecosystem. It is tolerant of extremely high temperatures but is susceptible to hard or prolonged frost. It is especially predominant in subtropical conditions as a weed in both annual and perennial crops and in pastures, fallows and waste areas. It occurs under semi-arid and irrigated conditions on a wide range of soil types of varying pH and salinity.
In Holm et al. A list of crops in which C. The crops in which it is most commonly a major problem are those of the subtropics that are planted in wide rows, for example, cotton, sugarcane, tobacco, citrus, olive, deciduous fruit, forestry and ornamental species and many vegetables, but also some closer-planted but less competitive crops such as rice, lucerne, mixed lucerne and grass pastures, onion and jute Labrada, The chromosome number reported for C. Ramakrishan and Singh and Sarandon have found differences in total biomass and biomass partition according to the origin of the population.
Riceweeds en – Cyperaceae – Cyperus difformis L.
Sarandon points out that characters are highly heritable, which means that high genetic variability for biomass production and variable rotudnus allows an ample base for selection, which in most cases is induced by herbicides, mechanical control or forage production. Quantitative traits such as seed yield and forage yield can be dramatically negatively affected by inbreeding depression Cook et al. In diploid populations, caryopses are formed after zygote formation.
In polyploids, which are sterile, caryopses may be apomictic. A photoperiod of 13 hours induces flowering. Low night temperatures coupled with high diurnal temperatures induces blooming Nir and Koller, A reduction in irradiance drastically decreases inflorescence production Moreira, Seeds may be the route of invasion in weed-free fields through the rotudnus of cows Rodriguez, personal communication.
Rhizome biomass exhibits an annual cyclic pattern and, as with any perennial weed, low temperatures reduce biomass and viability is lost as a consequence of the consumption of materials due to respiration and maintenance.
The digestibility of stocked material rptundus severely decreased, implying a loss in forage quality Vaz Martins, This is a character that has largely improved in cultivated varieties. Each node has a physiological self-governing structure in relation to the apex, but is highly klsaifikasi on substances from other plant parts. The mother plant determines the runner growth pattern on the cyperrus surface according to the sugar-gibberellin balance Montaldi Node disconnection may be caused by natural decay and cultivation and produces damage in the breakdown zone and changes in hormone and nutrient relationships.
It is widely demonstrated that rhizome or runner fragmentation induces the activation of buds. The proportion of activated buds increases as the number of buds per cypeurs decreases Moreira, ; Kigel and Koller, ; Fernandez and Bedmar, The cultivation method is mainly responsible for vegetative propagation fragmentation.
Cyperus esculentus (yellow nutsedge)
The higher the cultivation intensity, the smaller the segments produced Kigel and Koller, This weed produces an enormous number of small seeds 0. The seed is important because it confers high genetic variability on the population. Seeds remain viable in the soil for at least 2 years Caixinhas et al.
As a rule, cultivars have relatively high viability. Osmo-conditioning of Bermuda grass seeds with PEG followed by immediate sowing improved seed germination and seedling growth under saline conditions Al-Humaid The probability of emergence and successful establishment of C.
Growth from plants originated from a runner may exhibit a different biomass partition than that from plants originated from a rhizome Fernandez, Environmental Requirements The annual cycle of the weed starts with bud reactivation by the end of winter. There is no innate dormancy and buds can activate if adequate temperature and humidity is available at any time of the year.
Base temperature for bud sprouting ranging from 7. Aerial fractions have maximum dry matter content during the autumn and old rhizomes may have higher dry matter content than new rhizomes.
There is variation in tolerance to low temperatures and interactions between the time of exposure and relative humidity. Growth is favoured by medium-to-heavy, moist, well-drained soils but C.
A wide range of natural enemies of C. They include a mycoplasma-like organism, which causes pale foliage and commonly occurs in weedy populations. Damage from natural enemies is rarely sufficient to provide useful control. Many of the species listed as natural enemies are better known as polyphagous pests of poaceous and other crops, while others such as Sipha maydis require evaluation before being considered as potential biological control agents attacking inflorescences and leaves in India Labrada, Natural dispersal non-biotic factors such as water flooding, irrigation and agricutural practices contaminated seed and cattle husbandry propagate the seeds with released dormancy.
Also cultivators, chisels and drilling equipment allow runners and rhizomes to be distributed away from a given source. In their later book Holm et al. It is especially vigorous and pre-dominant in crops with wide spacing annual, such as cotton, and perennial, such as citrus where it suffers a minimum of shading.
Other crops in which it is a serious problem include rice, groundnuts, tobacco, sugar-beet, banana, pawpaw, pineapple, sorghum and many vegetables. Its exact competitive potential has rarely been measured but it is generally regarded as a highly competitive weed.
It has been listed among the top seven weed species in a world-wide review of weeds in sugarcane Cepero and Rodriguez, There is some evidence for allelopathic effects on peach Bengoa and Kogan, and on citrus Horowitz, but it appears klasifi,asi such effects may depend on the crop species and local conditions. In cotton, newly planted C. In an earlier study, monetary loss from C.
The competitive effects of C. A combination of C. Losses to all weeds in a number of the crops in which C.
As a major component of the weed flora in these crops over a substantial proportion of their total area, it is likely that C. Hood and Naiman klasifkiasi compared the invasibility of riparian plant communities high on river banks with those on floodplain floors for four South African rivers. Analyses of abundant and significant riparian species showed that the floors have rotindus.
Species richness and percent exotics are negatively correlated for the banks, but not correlated for the floors. Authors claim that the most prominent dyperus species are Lantana camara and C. Furthermore, the high proportions of exotic species in these riparian plant communities are comparable to those reported for vascular plant communities on islands.
They so conclude that the macro-channel floor regions of the riparian zones of South African rivers are highly vulnerable to invasion by exotic vascular plants. The pollen of C.
Purification and characterization of the isoallergen has been achieved by Chow