392 MR. C. C. LACAITA : A REVISION OF 
an satis diversa? — Diversissima a setoso Delile seu arenario Guss.,” and 
again in Heldreich’s exsiecata from that island under the name of 
Hi. arenarium B. Sieberi. This var. Sieberi was so named by De Candolle, 
Prodr. x. p. 21, and is based on an Egyptian specimen collected at the 
Pyramids by Sieber, which I have not seen. The Egyptian exsiccata 
most like Sibthorp’s plant and those from Naxos are a prostrate form of 
KE... sericeum, Vahl, from Ramleh, with subexsert stamens, which differ from 
Sibthorp’s difusum in possessing the adpressed pubescence of typical 
sericeum. J 
Boissier, Fl. Or. iv. p. 207, treats E. diffusum as a variety of sericeum, 
quoting it from Cos and Cyprus as well as from Crete and Naxos. This is 
right from his point of view, as he also treats Æ. angustifolium, Mill., 
as var. elegans of F. sericeum. But if angustifolium and sericeum are kept up 
as separate species and d//usum submerged, it is a problem to which of the 
former diffusum should be referred as a prostrate variety. The chief 
difference between those two species is in the indumentum—adpressed and 
rather silky in sericeum, but patent and hispid in angustifolium. That of 
difjusum seems intermediate, but to my eyes nearer to that of angustifolium, 
where it would also be preferable to place diffusum on geographical 
grounds. It seems best to retain diffusum as a species until much more 
copious material is available. 
The synonymy therefore is Æ. diffusum, Sibth. et Sm., Prodr. i. p. 125 
= E. sericeum, Halácsy non Vahl =Æ. sericeum, Vahl, var. diffusum, Boiss. 
= E. arenarium var. Sieberi, Heldr., exsice. non DC. 
IV. 
THE LINNEAN SPECIES OF ECHIUM. 
The chia of Linnzeus and his son comprise six South African species now 
referred to the genus Lobostemon; one from Asia Minor transferred by 
Boissier to his monotypic genus AMegacaryon; three shrubby species of 
Echium from the Atlantic islands, and nine European herbaceous species. 
It is only with the last that I propose to deal fully, as the Atlantic species 
and the Megacaryon offer no difficulty, and I am not sufficiently acquainted 
with the South African flora to say much about the Lobostemons, though 
two of these, nos. 1 and 6, raise problems of interest. 
Not all these nineteen species are represented in the Herbarium, which, 
however, contains three not mentioned in the Linnean writings, viz.: 
Lobostemon montanus, Buek, chium rubrum, Jacq.. and a small Echium from 
Spain which I cannot determine with any confidenee. 
I shall first enumerate the species, then the specimens, then offer some 
general remarks, and finally discuss the European species. As the sheets in 
the herbarium are not numbered, they are referred to by letters of the 
