OXALIS WAS NOT NEW CLOVER

Press, Volume CIV, Issue 30738, 30 April 1965, Page 6

OXALIS WAS NOT NEW CLOVER

Often one cannot but laugh when thinking back of some incident, stupid or otherwise, that occurred to one in the past. I never fail to get some cause for mirth from the time 1 thought I had discovered a new clover. Taking it to an eminent authority for identification, he looked at me pityingly and then he kindly suggested that I look up oxalis in a reference book before leaving me, then feeling somewhat foolish. The trofoliate leaflets are responsible for this mistake of what can become one of the most troublesome and difficult to eradicate weeds in the garden. Oxalis (in photograph), which is really its generic name, is sometimes commonly referred to as wood sorrel or yellow sour weed, consists of some 800 species, indigenous to Chile. Mexico, North America and South Africa. In America, England, the Netherlands and one or two other countries it is actually cherished as an ornamental. Adds To Menace

However, both in Australia and New Zealand this introduction quickly spread by division of the roots and bulbils, brought about by cultivation and by the farflung ejection of the seed from the pods formed after flowering has ceased. To add to the menace is the fact that these reproductive portions of the oxalis plant are capable of a prolonged period of inactivity or dormancy if conditions for growth prove unsuitable.

Apart from its amazing rapid powers of regeneration and spread this noxious weed also contains a very acrid juice, oxalic acid, which can cause serious internal troubles to stock which may eat it.

There are several fairly common species in New Zealand chiefly among them are the following: 0. corniculata, also known as small leaved oxalis or yellow wood sorrel, a very strong growing stoloniferous plant which spreads its low lying stems along the ground, rooting at every joint. If it invades the lawn it will kill the grass once it is established. Of Japanese origin, it has yellow flowers. The so-called Bermuda Buttercup or sour pod is a native of South Africa. Its botanical name is O. pes caprae, syn. 0. cernua. The leaves are blotched with purple spots and it is a bulbous type. O. ruba hails from Brazil and has red flowers and a rhizomatous root system.

Both O. hirta, red or pink flowers with a large bulbous root, and O. incarnata originate from the southern parts of Africa as does O. Purpurea which has dark, rounded,, hairy leaflets and purple flowers. These are some of the most prominent of the recorded species found in New Zealand.