SOME AFRICAN LABIATE WITH ALTERNATE LEAVES. 269 
had added yet two more. M. Hua, with great courtesy, sent us 
drawings of Icomum paradoxum; and by means of them we are 
assured of the distinetness of it from any of those which we shall 
here deseribe. Thus we know of five African Labiates which 
possess alternate leaves. 
Alternatiou of leaves is not by any means an unknown eon- 
dition in this order. Penzig * remarks its moderate frequency 
as au abnormality, and enumerates the following genera in whieh 
it has occurred : — Collinsia, Mentha, Hyssopus, Monarda, Physo- 
stegia, Leonurus, Lamium, and Dysophylla. Bentham also 
described an anomalous Hyptis under the name of H. anomala t, 
reduced later to H. conferta 1, which possesses alternating leaves. 
Alternation of the flowers of the iuflorescence, and of their braets, 
is well known in Scutellaria, where it characterizes a section 
( Heteranthera), and it also occurs in ZEolanthus. 
All these observations have served as a caution, which we have 
not disregarded. Yet it seems to us best to retain the genus 
Icomum, and under it we place four of the five plants above 
mentioned. 
Icomum is apparently closely allied to ZEolanthus—a genus 
confined to Africa, where most of its species occur within the 
Tropics. We thus diagnose the first-named, and arrange the 
plants by which it is constituted :— 
Icomum, Hua (loc. cit), Labiatarum-Ocymoidearum genus, 
ZEolantho maxime affine: distinguendum foliis alternis sepissime 
angustis, floribus in spicis siue ordine obvia aggregatis, bracteis 
floribus longioribus angustis: cæteris ab Zolantho non diversum. 
Spike compound. 
Corolla-tube narrow throughout........ J. paradoxum. 
Corolla-tube wide above ...... sess d salicifolium. 
Spike simple; corolla-tube only narrow in 
its lowest third. 
Leaves lineat................. ess T. lineare. 
Leaves oblanceolate-obovate .......... J. subacaule. 
* Pflanzenteratologie, ii. (Genoa, 1894) p. 231. 
+ Labiatarum Genera et Species (London, 1833), p. 113. 
4 Bentham in De Ca ıdolle’s * Prodromus, xii. (Paris, 1848) p. 112. 
CZ 
