Lavandula
Credits
Article from Bean's Trees and Shrubs Hardy in the British Isles
Recommended citation
'Lavandula' from the website Trees and Shrubs Online (treesandshrubsonline.
Family
- Lamiaceae
Common Names
- Lavender
Editorial Note
The text below, adapted and updated from Bean (1981) and Clarke (1988), combines the genus entry for Lavandula with that for the ambiguous taxon L. spica L. nom. rej., which (because of confusion in Linnaeus’s protologue) refers to two separate species, L. angustifolia and L. latifolia.
A genus of aromatic shrubs and herbs in which twenty-five species are recognised by Miss D. A. Chaytor in her monograph in Journ. Linn. Soc., Vol. 51 (1937–8), pp. 153–204. Inflorescence a distinctly stalked terminal spike. Fruits dividing into four nutlets. The species treated here belong to the sections Spica and Stoechas in both of which the spikes are cylindrical, with bracts arranged in opposite pairs, the fertile ones each subtending a condensed cyme with two to seven flowers; calyx and corolla tubular, the upper tooth of the calyx much enlarged. In this section Spica the bracts are uniform, all subtending flowers, and the corolla is markedly two-lipped and longer than the calyx. In the section Stoechas the uppermost bracts are sterile and form a conspicuous tuft known as the ‘coma’; the corolla-lobes are more or less equal; and the corolla-tube is not much longer than the calyx.
The genus ranges from the Atlantic islands through the Mediterranean to the Near East, India, and N.E. tropical Africa.
Taxonomic Note
Under the name L. spica, still commonly used in gardens, Linnaeus described two lavenders that almost all other botanists, before and since his time, have regarded as quite distinct species. These are the narrow-leaved, broad-bracted lavender L. angustifolia Mill, (the ‘true’ lavender), and the broad-leaved, narrow-bracted lavender L. latifolia (L. f.) Med., commonly known as ‘spike’. This was not an unusual situation, and no confusion would have resulted had there been agreement among botanists as to which of the two species should retain the name L. spica. Unfortunately, Linnaeus had chosen a misleading epithet for his compound species. At the time when he described it in his Species Plantarum (1753), the epithet spica was in use for both the lavenders concerned or at least was not yet of fixed meaning (Miller used it first for L. angustifolia, later for L. latifolia). But by the end of the century it seems to have become restricted to the broad-leaved lavender, whose oil was known as ‘oleum spicae’. So it is not surprising that many botanists, in the absence of any other clues as to the identity of the typical L. spica, used this name for the spike lavender. The ‘other’ lavender therefore needed a new name and in the event it received three – L. angustifolia Mill., L. officinalis Chaix, and L. vera DC. Other botanists of repute, however, considered that the typical L. spica was the narrow-leaved ‘true’ lavender, which Linnaeus described first, immediately under the heading. According to this interpretation it was the broad-leaved lavender (‘spike’) that had to be separated from L. spica, and for it the pre-Linnaean name L. latifolia was taken up.
Thus it came about that one name – L. spica – was used almost equally by botanists for two distinct species. In 1932, Miss M. L. Green proposed that L. spica should be discarded as a nomen ambiguum, in accordance with the rule that a name must be rejected if it has become a persistent source of confusion, and in the International Code of Botanical Nomenclature (ed. 1966), Art. 69, L. spica is actually cited as an example of such a name. The category of nomen ambiguum ceased to be recognised in 1975. The name was formally rejected under Article 56 of the Code in 2004 (see Applequist 2001, Brummitt 2004).
The two species involved in the confusion will be found in the present work under the names L. angustifolia and L. latifolia.
In gardens, the name L. spica has been used for horticultural varieties some of which are near to L. angustifolia (syn. L. spica of some botanists; L. officinalis Chaix; L. vera DC.), while others are clearly hybrids between L. angustifolia and L. latifolia (L. spica sensu de Candolle, Bentham et al). See further under these species.
The misuse of the name L. vera in gardens seems to be a result of the ambiguity of the name L. spica. It is often used at the present time for the so-called Dutch lavenders, which are near to L. latifolia and therefore far removed from L. vera DC. It is easy to see that this mistake could have arisen through wrongly equating L. spica Hort. with L. spica sensu DC., thus bringing de Candolle’s other species, L. vera, into equivalence with L. latifolia or hybrids near to it.
(For an interesting comparison, see the remarks of Clarke (1988) on the topic of Fraxinus angustifolia viz. F. rotundifolia Mill.)
