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Journal ArticleDOI

A micromorphological study of some representative genera in the tribe saturejeae lamiaceae

01 May 1990-Botanical Journal of the Linnean Society (Blackwell Publishing Ltd)-Vol. 103, Iss: 1, pp 59-80
TL;DR: HUSAIN et al. as mentioned in this paper performed a micromorphological study of some representative genera in the tribe Saturejeae (Lamiaceae) and showed that the structure of the nutlet surface and leaf indumentum can provide useful additional character combinations in delimiting these closely related genera.
About: This article is published in Botanical Journal of the Linnean Society.The article was published on 1990-05-01. It has received 74 citations till now. The article focuses on the topics: Indumentum & Micromeria.
Citations
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Journal ArticleDOI
TL;DR: The trichomes type of the calyx teeth, abaxial side of the leaf and latero-posterior corolla lobes can be used as a distinctive taxonomic character at specific and infra-specific level and supports Bentham's delimitauon of sections with the addiuons subequently made by Boissier.
Abstract: The micromorphology of trichomes of 56 Teucrium L. species belonging to the 9 sections of the genus in the Mediterranean area was surveyed by scanning electron microscopy (SEM) of leaves, calyx, corolla and nutlets. 25 trichome types are described, 12 of them are new. Thin walled hairs are the exclusive type found in the corolla and are the most widespread type on the abaxial side of the leaves. Subsessile glandular hairs, 2-4-celled, are found on the nutlet and leaves of the semi-shrubby and paleoendemic species. The presence of short or elongated, generally adpressed simple thick-walled slighuy conical hairs provides an additional character to clarify the boundaries between sect. Chamedrys (Mill.) Schreb, and sect. Polium (Mill.) Schreb. Branched non-glandular hairs are confined to sect. Polium subsect Polium , except for the rare branched hair conical and thick-walled type found in Teucrium barbarum Jahand. & Maire (sect. Chamaedrys ) and T. heterophyllum L`Her. from sect. Teucrium . This last section is well defined by the absence of simple slighuy conical thick-walled hairs and the glandular hairs in the corolla. Sect. Teucriopsis Benth, is of particular interest for the exclusive presence of branched and peltate glandular hairs on the nutlets surface. Sect. Chamedrys is a homogeneous group, distinguished from the other sections by an indumentum formed only by trichomes types evolved from the simple slighuy conical thick-walled hairs. This section overlaps, in the presence of glandular sub-sessile hair on the nutlets surface, with sects. Isotriodon Boiss, and sect. Polium subsect. Rotundifolia Cohen ex Valdes Berm. & Sanchez Crespo. The trichomes type of the calyx teeth, abaxial side of the leaf and latero-posterior corolla lobes can be used as a distinctive taxonomic character at specific and infra-specific level. This study supports Bentham's delimitauon of sections with the addiuons subequently made by Boissier.

117 citations

Journal ArticleDOI
TL;DR: Ecophysiological aspects of seed germination were investigated in the widely distributed Mediterranean-endemic, aromatic plants thyme, savory and oregano and it is suggested that this dormancy operates as an adaptation strategy that delays germination by acting as a rain gauge.
Abstract: Ecophysiological aspects of seed germination were investigated in the widely distributed Mediterranean-endemic, aromatic plants thyme (Coridothymus capitatus), savory (Satureja thymbra) and oregano {Origanum vulgare subsp. hirtum). Thyme seed germination is light indifferent, whereas oregano seeds have an absolute light requirement; their germination can be promoted even by green safelight or far-red light. In savory, a portion of the seeds germinates in the dark and germination can be either increased or decreased by the appropriate illumination. All three species show more germination at a relatively low temperature range, a Mediterranean characteristic, with an optimum around 15-20°C. The rate of germination is considerably higher in the tiny seeds of thyme and oregano than in the larger seeds of savory. In the latter species, germination is also dependent upon the age of the seeds; old seeds germinate to a higher percentage than fresh ones, as already observed by Theophrastus, possibly as a result of the volatilization of the essential oils present on the nutlet coat. Seeds of thyme, savory and oregano are dispersed within the persistent fruiting calyces and the seeds eventually germinate within it. Essential oils in the calyx strongly inhibit germination of the enclosed seeds; germination is much suppressed in thyme and to a lesser extent in savory and oregano. This diaspore dormancy caused by essential oils apparently is overcome under natural conditions by leaching of the inhibitors with rainwater. It is suggested that this dormancy operates as an adaptation strategy that delays germination by acting as a rain gauge. In this way, seed germination and subsequent seedling

114 citations

Journal ArticleDOI
01 Jan 2009-Flora
TL;DR: The data do not provide any support for separation of Sideritis from Stachys and trichome micromorphology is more useful in separation of species within sections rather than characterizing large natural groups known as sections.

65 citations

Journal ArticleDOI
TL;DR: The significance of nutlet microcharacters as additional taxonomical markers in the infrageneric classification of the genusTeucrium is discussed.
Abstract: Nutlet sculpturing of 23Teucrium species belonging to six sections was studied. The nutlets of analysed species were characterized by the presence of the oil glands of various density. SectionTeucrium is well defined by very densely distributed trichomes and oil glands on nutlets. Trichomes on nutlets were absent in all other species, except inT. marum from sect.Chamaedrys. Sect.Polium is a homogeneous group, distinguished from the other sections. There are some similarities of this sect. with sect.Scordium. Species of sect.Chamaedrys are heterogeneous and overlap according to the surface sculpturing characters with the other sections. The significance of nutlet microcharacters as additional taxonomical markers in the infrageneric classification of the genusTeucrium is discussed.

59 citations

Journal ArticleDOI
01 Jan 2010-Flora
TL;DR: Trichome micromorphology and distribution have high taxonomic value for Chelonopsis at both infrageneric and interspecific levels and supports Wu's delimitation of subgenus and sections and the subsequent review work by Xiang et al.

53 citations

References
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Book
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934 citations

01 Jan 1967

656 citations

Journal ArticleDOI
TL;DR: 6-hydroxyluteolin is present in the majority as a leaf constituent in some highly specialized herbaceous families and its distribution patterns indicate that the ability to hydroxylate flavones in the 6-position arose relatively late in evolutionary time.

79 citations