Thursday 3 September 2020

Species Spotlight Challenge - Day 29 - Prickly Saltwort

Prickly Saltwort (Salsola kali (or Kali turgidum according to some authorities)) is a succulent plant found on sandy shores round most of the coasts of Britain and Ireland. It is well adapted to living in these places, where what water there is is very salty and drains away quickly. It has fleshy leaves, which store water (like our spotlight species from Day 25 Sea Rocket, which grows in very similar places). The thick waxy cuticle and the rounded shape of the leaves (which minimises the surface area) help reduce the amount of water lost from the leaves by evaporation. The roots of the plant extend a long way downwards (to reach the water table deep underground) and horizontally, just below the sand surface, to allow the plant to capture as much water as possible from summer showers before it drains away. The sprawling, prostrate growth of Prickly Saltwort, and the rounded shape of the leaves, as well as (probably) the extensive root system, give it protection against the strong winds and waves that are frequent at the seashore - a taller plant, or one with broad leaves or shallow roots would easily be damaged or blown away in stormy weather.

The succulent tissues of Prickly Saltwort (as well as several similar salt-loving species) contain a lot of salty water and this led, in medieval times and even in the early industrial era, to the plant being very important in the making of both glass and soap. The whole plant was burned and the ashes mixed with water. Sodium from the salt in the plant's tissues would dissolve in the water, making a solution of sodium carbonate and the water was then evaporated off, leaving sodium carbonate crystals. These crystals were known as 'soda ash', also called 'alkali' (from the Arabic word for the substance - al-qali). In medieval times the name 'kali' was used for Prickly Saltwort and many similar  species. This is still reflected today in both of the scientific names for the plant (botanical authorities differ as to which is the most appropriate name to use so I have given both above).  












 

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