basal rosette
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2021 ◽  
Author(s):  
Julissa Rojas-Sandoval ◽  
Pedro Acevedo-Rodríguez

Abstract Tropical succulent perennial of 1.5-2 m height, with thick leaves in a basal rosette of elongated sword-shaped leaves from the base. Stems: Two to three years after transplanting, a 20 cm tall stem is formed, which will reach a height of about 1.2 m when flowering. White, fleshy stems develop from underground buds at the base of the plant, first growing sideways and then upwards to form new plants. These new plants are known as suckers (DAFF, 2015). Trunk: The plant base is a short trunk (30-150 cm), from the top of which the spirally arranged leaves grow (DAFF, 2015). The components of the dry weight of sisal fibre are approximately 55-65% α-cellulose, 11-18% hemicelluloses, 7-15% lignin, 1% pectin and 1-8% ash (Elzebroek and Wind, 2008). Leaves: Stiff, heavy, persistent leaves that are 0.6-1.2 m long, 10.2-20.3 cm wide, and 2.5-10.2 cm thick when mature. Leaves are spirally arranged around the trunk, greyish-green in colour and covered by a layer of wax. Leaves contain coarse, cream-coloured or pale-yellow fibres (3%) (DAFF, 2015). Young leaves may have small spines along their margins; they disappear when the plant matures. Leaves have a terminal, dark brown, rigid, very sharp spine, 2-3 cm long. The cross-section at the base of the leaf resembles a flattened triangle (Elzebroek and Wind, 2008). Inflorescences: A large panicle with flowers arranged on the terminal portion in dense clusters, sessile, 4-5 cm long. Perianths with 6 segments, 6 stamens, filaments longer than the perianth segment, 3-4 cm long anthers. Style exserted, stigma 3-lobed (EOL, 2018). It only flowers once at around 2 years. Before flowering, a flower stalk of 4.5-6.0 m develops from the growth point. The flower stalk subdivides to form branches that bear the flowers. The flowers do not produce seed, but form bulbils, which are used for reproduction. Bulbils are borne in the axils of the bracteoles of the inflorescence after flowering. Flowers are yellowish green, with reddish filaments. Roots: A. sisalana has a shallow, fibrous root system up to 60 cm deep. The 2-4 mm thick root arises from leaf scars at the base of the bole beneath the soil surface, and extends up to 5 m horizontally way from the mother plant, forming suckers. These can be used for propagation (DAFF, 2015). Sisal produces subterraneous rhizomes from buds in the axils of the lower leaves. Along the rhizomes there are buds that may grow into new plants, forming colonies. Most of the roots are concentrated in the upper 40 cm of the soil, where they spread horizontally up to 5 m. A number of roots grow deeper than 40 cm, which results in good anchorage (Elzebroek and Wind, 2008). Fruit: This species is monocarpic (i.e., dies after fruiting). Fruits are capsules up to 6 cm long, 2-2.5 cm diameter, stipitate and beaked. Capsules rarely formed, and seeds (if any) are probably not viable. Vegetative bulbils are commonly produced below the flowers in the axils of bracts (Weber, 2003; Acevedo-Rodriguez and Strong, 2005).


PhytoKeys ◽  
2020 ◽  
Vol 140 ◽  
pp. 107-123 ◽  
Author(s):  
S. Jost Casper ◽  
Rainer W. Bussmann ◽  
Tilo Henning

The insectivorous genus Pinguicula occurs along the whole Andean mountain chain from Colombia-Venezuela in the north to Tierra del Fuego in the south with a short interruption in the Peruvian-Chilean desert range. This paper describes a new and striking species of Pinguicula that occurs in the south-eastern part of the Amotape-Huancabamba Zone in north Peru. It grows either as a lithophyte on moist rocks or as an epiphyte on Polylepis multijuga Pilg. in the wet highlands of the Cordillera Central. Pinguicula rosmarieae Casper, Bussmann & T.Henning, sp. nov. is clearly distinguished by a basal rosette of ovate-obovate leaves spread out flat on the ground and especially by a two-partite corolla with a straight uniform tube-spur complex, two features unknown from other Andean Pinguicula species. The morphological similarity to P. calyptrata Kunth is discussed and the habitat and distribution of P. rosmarieae are characterised.


Phytotaxa ◽  
2019 ◽  
Vol 424 (4) ◽  
pp. 243-252
Author(s):  
MEI-JIAO ZHANG ◽  
WEI-JUN YU ◽  
HONG-QING LI

Ainsliaea simplicissima M. J. Zhang & H.-Q. Li, sp. nov., a new species (tribe Mutiseiae, Asteraceae) from Fujian, China, is described and illustrated based on morphological and molecular analyses. It can be distinguished by leaves situated in a basal rosette or aggregated at the lower part of the short stem, leaf blade narrowly elliptic or lanceolate, thick papyraceous, and capitulum bearing only one flower. The new species is morphologically similar to A. trinervis and molecularly sister to A. fragrans, both distributed nearby.


Phytotaxa ◽  
2019 ◽  
Vol 416 (1) ◽  
pp. 59-66
Author(s):  
EVA BENAVIDES ◽  
J.R. KUETHE ◽  
A. ORTIZ-ALCARAZ ◽  
J.L. LEÓN DE LA LUZ

Oenothera resicum (Onagraceae) is here described and illustrated. This is the first record of the Onagraceae family in the Revillagigedo Archipelago, Mexican Pacific. The new species, presently known only from Isla Clarión, has characteristic features of species of subsect. Raimannia, from which can be differentiated by its perennial habit, glabrescent large fruits, glabrous sepals, conspicuously dentated leaves, stigma surrounded by the anthers at anthesis, basal rosette absent, and its particular ecological habitat. The species description, ecological information, habitat and conservation assessment are also discussed. Additionally, a key for the species of  subsect. Raimannia distributed in Mexico is provided.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Anna Montefusco ◽  
Giuliana Semitaio ◽  
Pier Paolo Marrese ◽  
Andrea Iurlaro ◽  
Monica De Caroli ◽  
...  

We report the hydrophilic and lipophilic antioxidant activities, as well as the total phenol, flavonoid, tocochromanol (tocopherol and tocotrienol), and carotenoid contents in the edible portion of wild and cultivated varieties of chicory (Cichorium intybusL.) and in the basal rosette leaves of the wild species of poppy (Papaver rhoeasL.), known by natives as “paparina,” collected in the countryside of Salento (South Apulia, Italy). We analyzed (1) two cultivars of chicory, the “Catalogna” harvested in the area between S. Pietro Vernotico and Tuturano (Brindisi) and the “Otrantina” harvested in Otranto (Lecce); (2) two wild chicory ecotypes harvested in S. Pietro Vernotico (Brindisi) and Statte (Taranto), respectively; (3) the basal leaves of wild poppy harvested in Sternatia (Lecce). In all samples, our results showed that the hydrophilic antioxidant activity is, generally, higher than the lipophilic activity. Poppy leaves exhibited the highest hydrophilic and lipophilic antioxidant activities and the highest concentration of total phenols and flavonoids. Tocopherols were detected only as traces. Among the extracted carotenoids, lutein andβ-carotene were the most abundant in all analyzed samples. Total carotenoid content was greater in wild than in cultivated plants.


Phytotaxa ◽  
2013 ◽  
Vol 89 (2) ◽  
pp. 53
Author(s):  
LÉANNE L. DREYER ◽  
FRANCOIS ROETS ◽  
KENNETH C. OBERLANDER

Two new Oxalis species from the Richtersveld National Park (South Africa) are described and typified. Both species show strong morphological resemblance to members of the South African Oxalis section Cernuae. Oxalis nivea sp. nov. closely resembles the well-known weed O. pes-caprae, but it bears white flowers, and has a very restricted distribution range north of the northernmost known locality of O. pes-caprae. Oxalis rosettifolia sp. nov. is distinguished from all other species by a combination of a flat basal rosette of leaves, terete petioles, flask-shaped floral tubes and at least some enlarged, spathulate bracts at the terminal articulation of the peduncle. Phylogenetic analyses based on nuclear ITS and plastid trnSG data confirmed the placement of both of these species within a clade containing O. pes-caprae. The exact placement of these two species differs between ITS- and trnSG-based trees, but both analyses confirm a close relationship between the two new species and O. copiosa and O. cf. haedulipes.


Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1457-1465 ◽  
Author(s):  
Branislava Poduska ◽  
Tania Humphrey ◽  
Antje Redweik ◽  
Vojislava Grbić

Abstract The genetic changes underlying the diversification of plant forms represent a key question in understanding plant macroevolution. To understand the mechanisms leading to novel plant morphologies we investigated the Sy-0 ecotype of Arabidopsis that forms an enlarged basal rosette of leaves, develops aerial rosettes in the axils of cauline leaves, and exhibits inflorescence and floral reversion. Here we show that this heterochronic shift in reproductive development of all shoot meristems requires interaction between dominant alleles at AERIAL ROSETTE 1 (ART1), FRIGIDA (FRI), and FLOWERING LOCUS C (FLC) loci. ART1 is a new flowering gene that maps 14 cM proximal to FLC on chromosome V. ART1 activates FLC expression through a novel flowering pathway that is independent of FRI and independent of the autonomous and vernalization pathways. Synergistic activation of the floral repressor FLC by ART1 and FRI is required for delayed onset of reproductive development of all shoot meristems, leading to the Sy-0 phenotype. These results demonstrate that modulation in flowering-time genes is one of the mechanisms leading to morphological novelties.


1974 ◽  
Vol 52 (4) ◽  
pp. 913-918 ◽  
Author(s):  
Marilyn A. MacDonald ◽  
Paul B. Cavers

A previously unreported method of asexual reproduction has been found in Barbarea vulgaris. It involves the formation of a rosette of leaves (similar to those of the basal rosette) on the inflorescence after seed formation. If the stalk is bent to the ground, adventitious roots from the cauline rosette can become established. Eventually, if it survives overwinter, this new plant may bolt and flower.


1959 ◽  
Vol 52 (2) ◽  
pp. 161-167 ◽  
Author(s):  
J. L. Stoddart

The response of S. 123 extra-late-flowering red clover in the year of sowing to three sprayings of gibberellic acid (GA) given at 28-day intervals is described. Plants in both soil and vermiculite cultures were used.1. The first effects, noticeable in the basal rosette, were an increase in petiole length and a parallel increase in leaf area.2. Fewer stems were formed on the treated plants but their thickness and the number and length of the internodes were increased.3. Secondary branching was not significantly increased but the GA-treated plants produced a large number of tertiary branches from axillary buds on the secondary branches. Tertiary branching was not frequent in the control plants.4. Cauline leaves showed an increased length/breadth ratio at each node with treatment, elongation tending to be most marked at those nodes where leaf formation coincided with GA sprayings. Leaf thickness was also increased by GA treatment.5. Treated plants produced nearly 80% more heads, and flowering after GA treatment was up to 14 days earlier than the control.


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