A-Z of botany: Xerophyte

xerophyte

A xerophyte is a plant that is adapted to growing in an environment with low water availability. Plants have various ways of doing this so xerophytes do not all look alike, but there are various features that are common. Having a waxy or silky coat to the leaves or having small leaves reduces water loss (transpiration). Many plants produce leaves for very short periods when water is available, and then drop them, in a method similar to the growth of ephemeral annuals that ‘green’ the desert after rain and then disappear.

But the best known are cacti which have either no leaves or leaves that quickly drop (except for the primitive pereskia) and that store water in their swollen stems. Travel to any warm climate and you will see them planted. Cacti and other succulents (all <well most> cacti are succulents but not all succulents are cacti) show convergent evolution because cacti are plants from the family Cactaceae and are wholly from the New World while there are other, very similar-looking plants that have evolved in the Old World. Here many euphorbias (below – E. canariensis) have upright, spiny,ribbed stems that expand in width when there is water and contract when water is scarce, just like many columnar true cacti.

ruphorbia-canariensis-copy

Pachycereus, a true cactus.

pachycereus-weberi

There are other parallels too, like aloes (below) from the Old World..

aloe

And agaves (below) from the New World.

agave

Some of the most remarkable xerophytes of all are the tillandsias. Most bromeliads ( the family to which they belong) grow in shade and with plenty of moisture but these absorb moisture from the air and have scaly leaves that are able to survive extreme drought – and many actually grow on cacti.

tillansi

, , , , , , ,

No comments yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Ravenscourt Gardens

Learning life's lessons in the garden!

One Good Life in Los Angeles

Roslyn's observations about places and events around Southern California

IGPS Blog

The Irish Garden Plant Society - Lovers of Irish plants and gardens

AltroVerde

un altro blog sul giardinaggio...

vegetablurb

four decades of organic vegetable gardening and barely a clue

The Long Garden Path

A walk round the Estate!

Flowery Prose

Sheryl Normandeau's growing words....

ontheedgegardening

Gardening on the edge of a cliff

Uprooted Magnolia

I am a freelance Photographer born and raised in the Southeast. I have uprooted my life in Macon Georgia for a new life as an unlikely cowgirl in love with a handsome cowboy in Wyoming. I hope you enjoy my photo journal on life, love, and the spirit of Wyoming.

Interesting Literature

A Library of Literary Interestingness

Garden Variety

A Gardening, Outdoor Lifestyle and Organic Food & Drink Blog

For the Love of Iris

Articles, Tips and Notes from Schreiner's Iris Gardens

One Bean Row

Words and pictures from an Irish garden by Jane Powers

Plant Heritage

The world's leading garden plant conservation charity

HERITAGE IRISES

An English experience of gardening in Ireland - and back in the UK

%d bloggers like this: