Weeds of Australia - Fact Sheet

Top Scientific Name Synonyms Family Common Names Origin Cultivation Naturalised Distribution Habitat Habit Distinguishing Features Stems and Leaves Flowers and Fruit Reproduction and Dispersal Environmental Impact Other Impacts Legislation Similar Species

Scientific Name

Cynoglossum creticum Mill.

Synonyms

Cynoglossum pictum Ait.

Family

Boraginaceae

Common Names

blue hound's tongue

Origin

Native to southern Europe (i.e. France, Spain, Portugal, Italy, Albania, Greece and Bulgaria).

Cultivation

Not known to be deliberately cultivated in Australia, but a specimen was recorded to be growing in the Royal Botanic Gardens in Sydney in 1898.

Naturalised Distribution

This species has a limited naturalised distribution in the coastal districts of southern New South Wales (i.e. in the Eden district).

Naturalised overseas in South America (i.e. Argentina and Chile).

Habitat

Currently a weed of pastures and grassland communities in the warmer temperate regions of Australia. Overseas it also grows in disturbed sites, along roadsides, on sand dunes and in open woodlands.

Habit

A short-lived (i.e. biennial) herbaceous plant that grows up to 60 cm tall, but produces a basal rosette of leaves during the early stages of growth.

Distinguishing Features

• a relatively small and short-lived herbaceous plant (growing up to 60 cm tall).
  
  

• it produces a basal rosette of leaves during the early stages of growth.
  
  

• its alternately arranged leaves are hairy on both surfaces and are stem-clasping or borne on very short stalks.
  
  

• its blue to pinkish flowers are arranged along one side of a coiled stem that becomes elongated as the flowers open.
  
  

• these flowers (7-9 mm across) are blue to pinkish in colour with darker veins and have five petals.
  
  

• the 'seeds' are covered in numerous short, hooked or barbed, prickles and are borne in groups of four.

Stems and Leaves

Its stems are green in colour and densely covered with fine hairs (i.e. they are pubescent).

Its leaves (up to 20 cm long and 2.5-3.5 cm wide) are oblong to elongated (i.e. lanceolate) in shape and have entire margins. They are densely covered with long coarse hairs (i.e. they are pubescent) on both surfaces and have rounded tips (i.e. obtuse apices). The lower leaves are arranged in a rosette and are larger, while the upper leaves are alternately arranged and are reduced in size towards the top of the plant. The leaf bases are somewhat heart-shaped (i.e. sub-cordate) and stem-clasping (i.e. sessile) towards the top of the plant, while the rosette leaves are often borne on very short stalks (i.e. they are sub-sessile or shortly petiolate).

Flowers and Fruit

The blue to pinkish coloured flowers (7-9 mm across) are arranged in elongated clusters at the top of the stems (i.e. terminal racemes). They are borne on short stalks (i.e. pedicels) and are arranged along one side of a coiled stem that becomes elongated as the flowers open (i.e. this is sometimes called a boragoid inflorescence). Each flower has five green sepals (6-8 mm long), that become enlarged as the fruit begins to mature, and five petals (10-11 mm long). These petals are blue to pinkish in colour with darker veins and are fused together into a narrow tube (i.e. corolla tube) at the base. The flowers also have five stamens and a four-lobed ovary that is topped with a short style and a rounded stigma. Flowering occurs mainly during spring and summer.

Each flower produces four egg-shaped 'nutlets' (i.e. ovoid mericarps) that are initially joined together. These 'nutlets' (6-8 mm long) have outer surfaces that are covered in numerous short, hooked or barbed, prickles. They turn from green to brown in colour as they mature and eventually split apart when they are shed.

Reproduction and Dispersal

This species reproduces only by seed. The 'seeds' (i.e. mericarps) have hooks that easily become attached to shoes, clothing and animals. It this way the 'seeds' (i.e. mericarps) may be transported significant distances by animals or people.

Environmental Impact

This species is on the Alert List for Environmental Weeds, a list of 28 introduced plants that are currently not very widespread but are considered to pose a threat to Australia's environment. It is thought that blue hound's tongue (Cynoglossum creticum) has the potential to invade native grasslands and suppress native grasses in southern Australia.

Other Impacts

In other parts of the world this species is a troublesome pasture weed, and it could potentially affect the productivity of grazing and dairy farms in the wetter parts of southern Australia. Its leaves are also toxic to livestock (e.g. cattle and horses), and while cattle usually avoid it in the field, poisoning can occur when they are fed hay or chopped forage containing the plant. The burrs can also become attached to the hides of cattle, causing skin irritation.

Legislation

Not declared or considered noxious by any state government authorities.

Similar Species

Blue hound's tongue (Cynoglossum creticum) is very similar to the two native hound's tongues (Cynoglossum australe and Cynoglossum suaveolens). These species can be distinguished by the following differences:

• blue hound's tongue (Cynoglossum creticum) has relatively large flowers (7-9 mm across) and 'seeds' (6-8 mm across). Its stems are covered in small soft hairs and it does not have any small leafy bracts where the flower stalk joins to the stem. The flower petals are blue or pinkish in colour with prominent darker veins.
  
  
• austral hound's tongue (Cynoglossum australe) has relatively small flowers (3.5-6 mm across) and 'seeds' (2.5-3.5 mm across). Its stems are covered in stiff spreading hairs and it does not have any small leafy bracts where the flower stalk joins to the stem. The flower petals are blue or whitish in colour and do not have any obvious veins.
  
  
• sweet hound's tongue (Cynoglossum suaveolens) has relatively small flowers (less than 6 mm across) and 'seeds' (4-5 mm across). Its stems are covered in stiff spreading hairs and it has small leafy bracts where the flower stalk joins to the stem. The flower petals are white (rarely blue) and do not have any obvious veins.

It is also relatively similar to some of the forget-me-nots (Myostis spp.), which have similar flowers. However, the forget-me-nots (Myostis spp.) have smooth shiny 'seeds' without any prickles.