Medicinal and aromatic plants – industrial profiles

Section 3: 
Stoechas
Ging.
A distinct group of small woody shrubs with linear-lanceolate leaves. Diagnosed by their corolla
lobes that are all similar in size, the corolla tube only just exerted from the calyx, the broad ovate
to slightly obovate bracts and the capitate stigma, unique to this section. The flower spike is
dense and compact, each whorl of flowers (3–)5–7 flowered, minute bracteoles present. Apex of
16
Tim Upson
Figure 2.9 L. dentata 
var.
dentata
– Morocco. (See Color Plate IV.)

---

spike topped by a distinctive tuft of enlarged and coloured sterile floral bracts (a coma). The
coma differs from 
L. dentata
(the only other taxon bearing a coma) in being fully sterile and by
the shape of the bracts, which are linear lanceolate. Some of the earliest lavenders to flower from
late spring. The epithet 
Stoechas
is derived from the Stoechades Islands situated off southern
France (now known as the Iles de Hyères) from were the plant was first described by the Greek
physician Dioscorides.
Section 
Stoechas
, as circumscribed here contains just two species 
L. stoechas
and 
L. viridis.
This
hides the great diversity of taxa and variation that exists within this section as a multitude 
of infraspecific taxa are recognised under 
L. stoechas
. It is these taxa whose identity and true 
relationships remain both problematic and elusive. At present there is no completely satisfac-
tory treatment for the whole section and hence further research is being undertaken to address
these questions. The treatment given here is provisional and follows the most frequently used
classification purely for stability. Hence, no key is given to the subspecies of 
L. stoechas
as the
characters used to distinguish them are presently not fully understood and tested. A useful
treatment of the Spanish and Portuguese taxa is given in Suarez-Cervera and Seoane-Camba
(1989).
Key to species
Plant with green sterile bracts, leaves very glandular and sticky (viscid)  . . . . . . . . . .  
L. viridis
Plant with coloured sterile bracts, leaves not sticky  . . . . . . .. . . . . . . . . .
L. stoechas
and subsp.
5.