Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Tales from the Plant ID Service

Nettletree (<em>Trema</em> sp.) grown from seed in a banana shipment.

Nettletree (Trema sp.) grown from seed in a banana shipment.

The Allan Herbarium at Lincoln is a treasure trove of over half a million pressed and mounted plants and lichen specimens. “This nationally signifi cant collection underpins biodiversity and biosecurity research and management in New Zealand,” explained Ines Schonberger, who oversees the day-to-day operations. Earliest specimens are from 1769, collected by Banks and Solander during Captain Cook’s first voyage to New Zealand. While the key focus is on New Zealand plants, the herbarium has specimens from all over the globe.

The herbarium plays a vital role in weed management via its Plant Identification Service. Every year the herbarium receives more than 800 specimens for identification. “Some of the specimens are sent in by enthusiastic members of the public, but most specimens are sent in from agencies concerned with biosecurity such as regional councils, the Ministry for Primary Industries (MPI) or the Department of Conservation. Each year there are some interesting finds.

Recently staff were asked to identify plants originating from seeds found in a shipment of bananas from Ecuador. These plants were identified as nettletrees (Trema) in reference to their superficial resemblance to members of the Urticaceae. Trema are fast-growing pioneer trees found throughout the tropics and subtropics. Trema species are not currently present in New Zealand but are known to naturalise easily and have the potential to become invasive weeds here. Definitely one to keep out of in warmer parts of the country!

AgResearch sent in some plant specimens that had been grown (in containment) from seeds in soil collected from a shipping container loaded somewhere in the Pacifi c region. “Most of the 25 specimens identified belonged to taxa previously not known from New Zealand, and several of these taxa have weed potential,” confirmed Ines. While it is important to identify taxa brought into the country by accident, it is also important to voucher them to create a permanent record for future reference.

“Sometimes it is difficult for people to distinguish between native and non-native species,” said Ines. “Many genera contain both native plants and exotic species, for example Juncus edgariae is an endemic rush and very similar to the weed J. articulatus. Likewise, Carex dissita is endemic to New Zealand and C. longebrachiata is a weed,” she explained. Occasionally, “weed” specimens sent in turn out to be native species.

As well as terrestrial plants, algae and aquatic plants are often sent in. Recently algae on felt fishing boots from the USA caused alarm at the border. “However, we were quickly able to confirm that the sample contained Cladophora glomerata, a widely distributed freshwater alga that is already known from New Zealand,” said Ines. Other aquatic plants, attached to stalks of garlic originating from China, were identified as being Wolffia globosa, a free-floating plant measuring only 1 mm across. Wolffia globosa is found in East and Southeast Asia, Africa and Australia and has not been recorded from New Zealand.

As well as specimen identification, there are always changes to the nomenclature and taxonomy to keep up with. “Being up to date on names is critical for those charged with ensuring compliance with legislation outlining what plants are permitted entry into New Zealand, what species can be propagated or sold here, and what weeds must be controlled according to pest management strategies.

Sometimes, it is just information that people are after. For example MPI approached the Allan Herbarium to find out whether black grass (Alopecurus myosuroides), a potentially nasty agricultural weed on their watch list, is in New Zealand. Herbarium staff confirmed having no recent records of black grass (only one from 1941 in mid-Canterbury) and could not find evidence of specimens in any other New Zealand herbarium. Staff strongly recommended that MPI ensured no material of this species is allowed into the country. That was shortly before the news of a major accidental black grass seed spill in Canterbury hit the news headlines. The herbarium will no doubt now play an important role in documenting the success of efforts to mop up the spill.

For guidelines for sending specimens to the herbarium see Plant Identification and Information.

Funding to maintain the Allan Herbarium is provided by the Ministry of Business, Innovation and Employment. A small fee is generally charged to cover the cost of identifications.