Seed collecting in the Northern Cape
Read the diary of Dr Paul Smith, Head of Kew's Millennium Seed Bank, as he and colleagues undertake a seed collecting expedition in the Northern Cape region of South Africa.
Day 1: January 20 - Tswalu Game Reserve
We arrived here yesterday after two days driving from Cape Town (1,400 km). A beautiful place but dry and very hot. The temperature was expected to climb to the mid-forties today. We therefore planned do our seed collecting in the early morning and late afternoon/evening, avoiding the hottest part of the day.
The seed collecting team is made up of Livhu, Sarah and Zoleka from the South African National Biodiversity Institute (SANBI), and Jonathan and myself from Kew. Today we were joined by Corne, our local guide.
Livhu had already checked our seed list against the plant checklist for the Reserve, and found around 50 species that we don’t have in the Millennium Seed Bank. The trick, however, is to find the plants in seed.
Our first stop was the rocky hills that are found in the east of the Reserve. The dominant vegetation type in this part of the Kalahari is Acacia wooded grassland – mainly Acacia mellifera, A. erioloba and A. hebeclada. Rhigozum trichotomum is another important woody species. The grass layer is largely made up of Stipagrostis, Eragrostis, Anthephora, and Enneapogon desvauxii in the calcareous areas.
Here in the hills we were able to make a large collection of Andropogon gayanus, a grass that is used in C4 photosynthesis research, and which was on our hit list. An unexpected treat was seeing mountain zebra galloping past as we made our collection.
From the hills we went down on to the plain where we were able to collect three other species, including Ehretia rigida, a shrub used for medicinal purposes. By this time it was midday, and we were pretty dehydrated so we headed back to camp for lunch.
After lunch we were joined by Sam and Zandri, two local researchers who had offered to show us the major habitats in the park. We climbed aboard their 4 x 4 to tackle the Kalahari dunes, and drove from east to west – a full transect of the park – stopping in each habitat to look for seeding species. We found a number of plants that we are after but, unfortunately, none was in seed. Their localities were noted for future visits however. Thus ends our day in Tswalu. It’s a lovely place that the team will come back to. We left a few collecting bags with our friends there.
Day 2: January 21
A very long drive today (1,100 km) in which we traversed the Northern Cape pretty much from top to bottom. Our route took us past towns with evocative names such as Hotazel and Pofadder. Sarah and I shared the driving. Spectacular scenery and empty roads made it a pleasurable experience. Our destination was Nieuwoudtville, the bulb capital of South Africa, and home to SANBI’s newest botanic garden, 'Hantam'.
We arrived in Nieuwoudtville at about 7pm, found our B&B, and had an early night.
Day 3: January 22
We teamed up with Hantam staff first thing this morning, led by Eugene, the curator here. Also joining us were Arika, Raymond, Gershwin and Mercia. Hantam Botanic Garden is an 8,000 hectare nature reserve comprising parcels of richtersveld, karoo and fynbos vegetation. This morning we headed out to the Hantam fynbos, our main target being the endangered species Leucadendron remotum. We were delighted to find it in fruit, but found that most of the cones were infested with insects. Fortunately, Eugene’s team had noticed that some of the seeds on the ground under the shrubs were intact. We spent about three hours at this site collecting the Leucadendron and several other species.
After lunch, we moved to a different part of the fynbos, looking for the wild ‘rooibos’ (Aspalathus linearis) from which the famous tea is made. Unfortunately, the plants were still in flower, and there were no seeds to be seen.
Further on we found a vlei and stream where we were able to make five good collections that included two Crassula species and a Juncus (rush). By this time it was 6.30pm, and time to head for home.
Day 4: January 23
Today we went out to one of the areas of Hantam Karoo vegetation. We were amused to see our Hantam colleagues in the car ahead suddenly screech to a halt then all climb out on to the car looking in one direction like a family of meerkats. They had spotted a spitting cobra in the road.
At our first collecting site, we collected several succulent species from the family Mesembryanthemaceae (Aizoaceae). Many of these plants produce anthocyanins – red pigments – to protect them against the strong sun. They reminded me of the most intricate of Turkish rugs. These plants are difficult to identify to species, and our collections will go to specialists who will be able to name them for us. They are easy to collect, however, with each capsule containing up to 40 seeds.
In the afternoon, we walked down into a nearby gorge where there is a seasonal stream (dry at this time of year). Here we were keen to collect seeds from two tree species – the Namaqua fig (Ficus cordata) and the silky wing pea, Wiborgia sericea, the latter being a Cape endemic. We were able to collect lots of seeds from the wing pea but our initial investigation of the fig revealed no fruit on the tree. However, when we looked on the rocks below, we found large drifts of seed in the rock crevices, and were able to collect these. We made several other collections in the gorge, including Galium tomentosa (a climber) and a white flowered Salvia species.
Day 5: January 24
The last day of our trip, sadly. We headed back to Cape Town via the Bottekloof Pass, the Cedarberg mountains and Clanwilliam. Awe-inspiring scenery, particularly the Cedarberg with its towering sandstone cliffs and buttes, looking like something out of a cowboy movie. The Cedarberg is home to the highly threatened Clanwilliam cedar, Widdringtonia cedarbergensis, a species we will have to come back for.
We got back to Cape Town by about 6.30pm. Our total tally over the past five days was 44 high quality seed collections, including both rare and threatened species. This is a tribute to the SANBI teams at both Kirstenbosch and Hantam, and I am extremely grateful for their hospitality and dedication.
- Paul -