Signa demum sunt explicanda, quibus subspecies, varietas, etc. in- 
dicandas utimur. Subspecies ideo (litteris minimis impressae) notan- 
tur asterisco (*), ee: 
Nevertheless, the asterisk was also frequently em- 
ployed to signify a subspecific variant of doubtful worth 
or the exact rank of which was uncertain. Persoon (Syn. 
Plant. 1 (1805) x) used it thus: 
Speciebus obscuris, aut quoad sedum accuratori indagationi subji- 
ciendis, signa crucis seu asteriscum apposui. 
I believe that it is in this sense that Mueller used the 
asterisk, for we find a clear example of this use in Muel- 
ler’s own writing (in DC. Prodr. 15, pt. 2 (1866) 749) 
under Crozophora tinctoria B Hierosolymitana: 
Haec ludit * brachypetala, petalis florum foemineorum calyce paulo 
v. duplo imo 4-plo brevioribus. 
In this case, we might call the variant a forma today ; 
Mueller usually employed Greek letters for varietas, so 
that it is probable that he thought of the asterisk in this 
particular instance as a subvarietal variant or forma. This 
indirect evidence, coupled with his statement that the 
variant of Hevea pauciflora which he was calling mem- 
branacea ‘‘praeter consistentiam foliolorum nullo modo 
recedit’’ from the species, convinces me that the epithet 
membranacea was first published as a forma. 
In his description of Hevea pauciflora forma membra- 
nacea, quoted above, Mueller based the concept on a 
collection made by Richard Schomburgk and preserved 
in the Berlin Herbarium. Then, a few years later (in 
Martius FI]. Bras. 11, pt. 2 (1874) 299) he raised the con- 
cept to specific rank under the name Hevea membrana- 
cea, giving a much fuller description. In so doing, he cited 
Spruce 2691 as the only collection referable to Hevea 
membranacea; Spruce 2691 was already the type of HZ. 
pauciflora! He failed to enumerate the Schomburgk 
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