Before leaving our discussion of Hevea Kunthiana, we 
should consider the history of the binomial HZ. membra- 
nacea and of the various other combinations in which the 
epithet membranacea has been used. Hevea membranacea 
as a name has no biological significance whatsoever, for 
Mueller described the concept from the same collection 
(Spruce 2691) that was already the type of H. pauciflora. 
The epithet membranacea has, however, persisted in the 
literature and has been bandied about in the nomencla- 
ture to such an extent that much uncertainty might 
easily be experienced by rubber investigators who are not 
familiar with all of the intricacies of the problem. 
The first published mention of the epithet membranacea 
was made apparently in 1866, when Mueller-Argoviensis 
(in DC. Prodr. 15, pt. 2 (1866) 718 wrote the following: 
Ludit * membranacea, foliolis tenuiter membranaceis. [tree]. In 
Guyana anglica cum forma genuina speciei (Rich. Schomb. in hb. 
berol!), Haec praeter consistentiam foliorum nullo modo recedit. 
It is not clear just what Mueller meant by the use of 
the asterisk, but it is important to attempt to clarify his 
meaning, if possible. This sign is not included in the 
enumeration of signs at the beginning of volume 15 of 
the Prodromus, so it must have been used in a sense 
which, at the time, was widely understood. Mueller 
might have employed the asterisk to mean subspecies or 
variety, for it was often used during the 19th century 
to designate subspecific variants, especially subspecies. 
Persoon (Syn. Plant. 1 (1805) ) was apparently the first 
to use it in this way. An example may be cited (I. ec. 
2 (1807) 41): 
Mesembryanthemum 4. linguiforme a scalpratum Obs. Tres. sequentes 
tantummodo subspecies videntur: * datum, * obliquum, * longum. 
Each of these subspecies is described. Another example 
from later in the century is that used by C. F. Nyman 
(Consp. Fl. Europ. 1 (1878) pg. ant. pg. 1): 
{ 260 | 
