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IDENTITY OF SPECIES WITHIN Serruria section Acrocarpae

Certain species of Paw Spiderheads (section Acrocarpae) are giving atlassers severe headaches. The section contains some 10 described species. All are characterized as having curved florets in a solitary head, lacking showy involucral bracts, on a conspicuous stalk. The group is best divided into three sections:

Section 1: Plants creeping or low-growing.

S. cygnea, effusa, incrassata. On Jonaskop an undescribed species resembles S. incrassata. These species can fairly easily be distinguished by their growth habits (PAN 9: 4) and geographical distributions.

Section 2: Plants erect with hairless styles.

The three species in this section may be distinguished as follows, with leaf colour, flower stalk and floret hairs as among the most useful features (PAN 9: 4):

S. aitonii: leaves silver, robust; perianth hairs spreading; peduncle 5-30mm long;

S. reflexa: leaves silver, robust; perianth hairs spreading; peduncle 50-70mm long;

S. fucifolia: leaves grey, sparsely haired, thin; perianth hairs adpressed; peduncle 20-60mm long.

Section 2: Plants erect with hairy styles.

These are the only Spiderheads with hairy styles. They are thus very easy to separate out as a group on their own. However, distinguishing species within this group has proved almost impossible.

The problem does not reside so much in the plants. Rather it is a combination of us dealing with four validly described species, two possible additional undescribed species, and several old species names which should be declared synonyms. If this was the extent of the problem, there would be no problem! Unfortunately, all the species are very poorly known and insufficient herbarium material is available to John Rourke to adequately resolve the problem. No sooner has John come to a decision than another specimen turns up which requires John to rethink all his ideas.

Two species in the section are easy to distinguish:

þ S. flava: short leaves with a red tip, florets yellow.

þ S. acrocarpa: the only resprouter in the section. Flowers usually yellow, but not uncommonly pink, perianth hairs adpressed. The leaves age to hairless. Unless atlassers record the habit of this species (resprouting) it can be confused with some of the remaining species.

This leaves us with just three species to consider (John states that there is another type specimen which might be a separate species, but until he is certain he refuses to confuse us further). The dianostic features for these species, as they are currently defined, are:

þ S. non-acrocarpa (see Protea Atlas Manual: 25) has spreading silver hairs on the perianth. It occurs in the Langeberg (Garcia's Pass & Montagu), and is thus geographically distinct.

The major regions of confusion are the Worcester Valley and surrounding mountains, especially in the Ceres and Slanghoek areas. These species may have to be redefined depending on new data that might turn up. If you are visiting the area and have a collectors permit, please collect voucher specimens so that the issue might be speedily resolved. Please remember to take notes on plant height, habit and colour: most additional data can be gleaned from your Sight Record Sheets. Should you be visiting the area and require a permit to collect Spiderheads, please contact Chris.

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