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WILDLIFE OF NORTHERN ENGLAND

Basic plant biology-3 Foliage and their function -2

On the page Plant,Basic Biology-2 foliage and their functions were reviewed. Looking at the type of leaves that adorn different species. On this page the shape of the foliage including botanical terms attributed to them. The term for the study of these shapes is leaf morphology.

I will once again try to keep the text as simple as possible. Even the tips of the leaves have their botanical terminology. If one has the basic knowledge of these terms it will help in identification of a subject. Most wild flower books and indeed many books identifying cultivated flowers will use these terms when describing the foliage of the plants.

Many of the terms describe the different shape of the leaf tip, below is a cross section of these terms.

ACCUMINATE---From the Latin accuminare meaning to sharpen. This tips in this type of leaf are long pointed,tapering into a prolonged narrow tip in a concave manner.

ACUTE--From the Latin acvere also meaning to sharpen. From acus meaning a needle, this type of leaf tip end in a sharp, but not prolonged point.

Below the linear acumminate foliage of the stitchwort.

photograph -Dal

Cupsidate--

CUPSIDATE---From the Latin cupsidare, meaning to make pointed from cupus a point. These leaves narrow to a point.

OBTUSE--From the Latin obtusus meaning dulled, this type are rounded or blunt.

TRUNCATE---From the Latin truncare meaning to lop, this type end abruptly with a flat end that looks cut off.

APEX TOOTHED--- teeth at the tip.

Terms for the base of a leaf.

 ACUMIATE  AND ACUTE  See above.

AURICULATE--From the Latin auris meaning an ear, the base of the leaf ends in an ear shaped lobe.

CORDATE--Heart shaped with a notch towards the stalk.

Below the cordate leaves of the lesser celandine

photo Dal

Cuneate

Cuneate-wedge shaped.

HASTATE---From the Latin hasta meaning a spear, shaped like a halbard , basal lobes pointing outward.

RENIFORM--From the Latin renis, meaning a kidney. Kidney shaped but rounder and broader than long.

ROTUND-- Rounded leaves.

SAGGITATE-- From the Latin sagitta meaning an arrow. The arrow shaped foliage with acute basal lobes pointing downwards.

TRUNCATE--ending abruptly, as though cut off.

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Let us now review the surface of the leaf. The botanical names to describe the leaf surface,--these include-----

Farinose---bearing very short waxy, whitish powder.

GLABROUS-- from Latin glabra, meaning bald or smooth.

GLACOUS--From Latin glacous meaning silvery, bluish-green with a ehitish bloom.

GLUTINOUS--  Viscid and sticky.

PUBESCENT--Covered with erect hairs, especially soft and short ones.

RUGOSE--From the Latin ruga meaning a wrinkle. Leaves a re deeply wrinkled.

VERRUCOSE--From the Latin verruca, meaning a wart, the leaves are covered with a warty prominence.

VISCID--From Latin viscum meaning mistletoe {or bird lime}--covered in sticky secretions.

Foliage texture

Many species of plants and trees have evolved to have their surfaces covered with hairs which vary greatly in thickness and shape. This covering of hairs on differing species have various functions. Some types hold moisture in so has to prevent water loss. Others reflect the rays of the sun so as to protect the surface from getting to hot. Hairs on many perennials are to protect the surface from frost and ice.

The hairs { botanist refer to them as trichomes} have many botanical terms alluding to the type of hairs, theirtexture or appearance. Examples are------

GLANDULAR-- With a gland at the tip of the hair.

LANATE----With woolly hairs.

STELLATE---with star shaped hairs.

TOMENTOSE--densely matted with soft whit woolly hairs.

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The surface of the leaves may be waxy which reduce water loss. Succulent leaves store water and other nutrients.Some have aromatic or toxic qualities to prevent grazing. Some plants have leaves that are adapted- a transformation into tendrils to help them climb. Many members of the Fabiaceae {bean and pea family} adopt this strategy. Others adapt a transformation into bracts. 

BRACTS--Are modified leaves, especially when associated with a reproductive structure such as a flower. Bracts are often different in form from the true leaves { but not always so } being larger or smaller, or differing in colour or texture to the unmodified leaves of the plant. Some are  brightly coloured and thus are there to attract pollinators.

Bracts that appear in whorls surrounding the stem beneath the flower are collectively known as the involucre. The daisy family in particular have many species with such bracts are present. Coltsfoot have bracts on the flower stems and an involucre.

BELOW .The flower stem of the coltsfoot. There are bracts on the stem and below the flowerhead {the involucre.

 Courtesy of R A Nonenmacher  CC BY-Sa 4.0 License.Tussilago farfara SCA-01305.jpg

leaves---continued

Leaves that grow in the shade tend to be thinner and adorned with less hairs  and of a larger size than those on the same plant/tree that are exposed to direct sunlight. The foliage of plants that tenant dry, hot regions, generally have thicker leaves and of a more leathery texture.  Many will be adorned with succulent leaves, and, in some cases, lack foliage altogether, in this case the stems tend to be covered by hairs. Many desert plants have modified leaves in the form of spines.

Plants of the Fabiaceae {pea and bean family} have modified leaves that turn in to tendrils to help them to climb or for support.

Below---The bush vetch has modified leaves {tendrils} to help them climb and used for support.

photo Dal

A CONCLUDING GLANCE AT FOLIAGE SHAPES.

LINEAR-- greater stitchwort. Stellaria hostea

LANCE SHAPED--Ribwort plantain , Plantago lanceolata.

ELLIPTICAL-- Bog bean Menyanthes trifoliata.

OBLONG--Primrose, Primula veris.

SPOON SHAPED--Common daisy Bellis perennis.

KIDNEY SHAPED--Butterbur, Petasites hybridus.

HEART SHAPED--Lesser celandine Ranunculus ficaria.

 

shapes phototographed  Top the sheathed foliage of angelica--Next to top--the scalloped leaves of lady,s mantle. Next to bottom-the lobate leaves of oak--bottom  the meadow sweet has pinnate foliage.--Photographs by Dal

pp

Finally---

As we can see leaves are important to plants and trees they are also vital to humans for such as leaf vegetables and leaf salads, and of course for medicinal purposes. They also have an importance in aesthetic values such as flower arrangements .

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Associated pages, click on the relevant content banner at the top of this page.

Plant Basic Biolgy--1

Plant Basic Biology--2

Plant Basic Biology-4

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