RHODOPHYTA OF TROPICAL AFRICA 77 



Selection of the specimen to be regarded as typotype (as defined in Stearn, 1957 : 128, 129) of 

 Porphyra umbilicalis (Ulva umbilicalis L.) is complicated. Linnaeus (1753 : 1163) is known to 

 have utilized mainly the description and illustration provided by Dillenius (in Ray & Dillenius, 

 1724 : 45, 46 and tab. VII, no. 3) as the basis for Ulva umbilicalis L. Whilst the illustration thus 

 has to be selected as type for that species, the specimen (typotype) on which the illustration was 

 based remains critically important. There are three known specimens of potential importance 

 here; all were utilized by Dillenius at different stages. The specimen in the Historica Muscorum 

 Herbarium, Oxford, is not localized and cannot be directly connected with collections from 

 Sheerness (Kent), the only locality cited by Dillenius for the species in any text. This specimen is 

 therefore initially set on one side for typification purposes; in any case, the specimen does not 

 accord well with the Dillenius illustration in Historia Muscorum. Other specimens in the William 

 Sherard Herbarium and in the Dillenian Synopsis . . . Herbarium, both University of Oxford, 

 are localized by Dillenius to Sheerness and are of importance. Druce & Vines (1907) and Clokie 

 (1964) have emphasized that few specimens bearing dates are extant throughout the Synopsis 

 Herbarium; those that are dated were mostly collected by Dillenius and placed in that Herbarium 

 after 1723, both as illustration of the concept in the 1724 (ed. Ill) Synopsis . . . and in preparation 

 for a proposed fourth edition. Dillenius had only been in England from August 1721 onwards 

 and would therefore necessarily have made use of extant herbaria, supplemented by his own 

 restricted collections from 1721 to 1724. Most of the extant herbarium material that he employed 

 was in the fine herbarium of his patron, William Sherard; Dillenius himself added many further 

 specimens to that herbarium. 



Specimens utilized during preparation of Synopsis (ed. Ill) were both copiously annotated in 

 in Dillenius's hand and labelled by means of excised entries from a copy of this 1724 work; 

 this applies both to specimens already in the collections and to those added by Dillenius. Of the 

 three specimens of Porphyra umbilicalis in the William Sherard Herbarium, one is lettered 'G' 

 on sheet and labels, and bears both MS Dillenius ('Lichen marinus Lob. Ic. II. 247. J.B. Ill 

 L. 39. c. 61. p. 813 C.B. Pin: 364. 2' and 'Sherness'; later 'Tremella marina umbilicata Hist.') 

 and an excised text of Synopsis . . .Ill: 62.2 entry. The other two are not important here. It is 

 clear that 'G' is a major specimen in context of the Dillenian concept of P. umbilicalis under 

 Ulva marina umbilicata (Synopsis III, 1724) and Tremella marina umbilicata (Historia Muscorum, 

 1742). Probably this specimen was one of those that Dillenius did collect himself in the 1721-24 

 period; all annotations of the period on the specimen are in Dillenius's hand and the entries 62.2 

 (Synopsis III) and 45-46.3 (Historia Muscorum) both indicate '. . . observataque mihi pone 

 Sheerness . . .'. The later annotation on the specimen by Dillenius of the name used in Historia 

 Muscorum indicates that it was also consulted for the latter work. By contrast, the specimen now 

 in the Dillenian Synopsis Herbarium (62.2) is simply annotated with the Synopsis name and 

 without later additions; it was probably not consulted for Historia Muscorum. 



The pre-1724 Sherardian specimen is in rather better agreement with the 1742 illustration 

 than is the post- 1724 Synopsis Herbarium specimen. Original drawings made by Dillenius for 

 the Historia Muscorum illustrations (in BM*) show very good agreement as to the form of 

 lobation between the original Dillenius drawing and the Sherard Herbarium specimen, whereas 

 that between the Synopsis Herbarium specimen and the original drawing is not so good. This 

 comparison is slightly complicated by alteration in the process of drawing or engraving for 

 publication; the image is reversed and two extra small lobes are added at upper right of the 

 published illustration. The Sherard specimen remains much nearer in overall form. It is, of 

 course, quite possible that the Historia Muscorum illustration is some sort of amalgam of impres- 

 sions from more than one specimen. Even in the light of that possibility, the specimen 'G' in 

 the William Sherard Herbarium is so much nearer in form that it should be designated typotype, 

 and we formally so designate it. In this matter, we are unable to agree with L. M. Irvine (who has 

 annotated the Dillenian Synopsis Herbarium [post- 1724] specimen as typotype) and even less 

 so with Conway (1964 : 349 and pi. I, fig. 2), who has figured as typotype the Historia Muscorum 

 specimen, without stating clearly that it was from that Dillenian Herbarium. 



*In this publication BM = British Museum (Natural History), London. 



