118 Janies Small. 
type, e.g., Spharocotna in the Caryophyllaceae (cp. 1, Tab. Ill), 
where the involucral bracts are few, small and green ; Posoqueria 
detisiflora (Rubiaceae) where there is practically no receptacle and 
an indefinite involucre of a fe’w foliage leaves; and Monarda in the 
Labiatae (see below). 
It may be of interest to note the condition of the involucre 
in some of these families. In the Monocotyledons Alisma 
Plantago shows cymose umbels with a simple involucre very 
similar to that of the proliferated Helenium observed by Masters 
(11,48); Narthecium ossifraguin may be taken as an example of the 
common phenomenon of progressive crowding in a raceme with 
bracts and pedicels present, spacing taking place later in the fruiting 
stage. In the crowded spikes of many orchids bracts are usually 
present. 
Among the Dicotyledons we have the phenomenon of pro¬ 
gressive crowding very marked in the Cruciferae, where the bracts 
are absent; this with the corymbose habit gives an approach to 
the racemose umbel. In the Leguminosae dense racemes are 
common; the pedicels are frequently very short and the bracts 
much reduced or absent. An involucre is comparatively common 
in these heads, and may be composed of a few of the outer fertile 
bracts or 1-2 slightly modified cauline leaves. 
In the Araliaceae ( Hedera and Aralia), the inflorescence is a 
racemose umbel with the bracts much reduced or absent and no 
involucre. The Umbelliferae frequently show the umbel with only 
the outer bracts forming a uniseriate involucre, but the development 
of more rows of involucral bracts occurs whenever the inflorescence 
becomes denser, as in Sanicula , where it is uniseriate or indefinitely 
bi-seriate, and Astrantia , where it is bi- or tri-seriate. 
The cauline origin of the involucre in Monarda is seen clearly 
in the Labiatae, where there is a distinct tendency towards shorten¬ 
ing of the internodes immediately below the inflorescence. This is 
well shown in many common Labiatae, such as Prunella vulgaris 
and Ajuga replans , and a similar phenomenon is seen in Campanula 
glomerata. 
In the Campanulaceae the umbel of jfasione, like that of 
Astrantia, has a pluriseriate involucre. The usual tendency in 
the Lobelioideae is towards dense spikes with many large foliaceous 
bracts, but racemose umbels occur also, notably in Siphocampylus 
spp. Below these umbels there are usually a few normal foliage 
leaves, somewhat crowded on account of the shortening of the 
internodes as in the Labiatae. 
