THE MORPHOLOGY OF THE PRIMULACEZ. 728 
segments are free. Attached to the corolla-tube, and superposed to its segments, are the 
five stamens. 
In Glawx the corolla is wanting. Іп Samolus five scales emerge from the throat of 
the corolla, alternating with the stamens, which naturally suggests the notion that they 
represent an outer row of stamens, which in most cases is suppressed*. In a double- 
flowered Cyclament lately examined by me there was a double row of petals, the inner 
occupying the position of the scales of Samolus. 
Others consider that the petal and the stamen are in this case not two distinct parts 
but two divisions of the same part. Thus Duchartre? 
describes the petals as appearing after the stamens as уњ. о 
а sort of appendage or dédoublement:—“Elle (the GEBEN 
corolla) ne constitue en effet dans l'origine qu'un bour- 2 | 
relet ou un petit repli qui entoure la base du verticille 
staminal" Van Tieghem $, basing his opinion on tlie 
faet that a common fibro-vascular bundle divides into 
an outer and an inner division, the former for the petal, 
the latter for the stamen, comes to the conclusion that 
stamen and petal form part of the same phyllome. 
А similar conclusion is arrived at by Pfeffer|| from 
the study of the development of the flower. He shows 
that within the calyx five small tubercles are deve- 
loped, alternating with the sepals. Hach of these tu- 
bercles ultimately develops into a stamen; and from 
the outer surface of this stamen is gradually protruded 
the petal. According to this view, then, the Primrose has, morphologically, no corolla, 
the petals being merely outgrowths from the stamens €. 
Development of the Parts of the Flower.—M y own observations on the development of 
the flowers of Primula and Lysimachia lead me to a slightly different conclusion. In 
the first place, the mode of development does not appear to be uniform in the same 
genus; thus in some specimens of Lysimachia nummularia it has appeared to me that 
the petals did really sometimes (but not always) precede the stamens in their develop- 
ment. When this happens the latter advance so much more rapidly that they speedily 
outstrip the petals, and appear as if they had preceded them. If this be really so, the 
petal, instead of being an outgrowth from the stamen, is, in such cases, the organ from 
which the latter proceeds (Plate XXXIX. figs. 10-23). Many double Primroses, in 
which petal succeeds petal, one in front of another, the inner bearing a stamen, support 
this view. - 
In normal Primroses the course of development, according to my observation, is as 
Cyclamen with leafy calyx, referred to in 
the text. 
+ *Gardener's Chronicle, March 17, 1877 
* Richler, Bliithen-Diagramme, p. 327. 
$ Ann. Se. Nat. 1867, ix. р. 135. 
+ Ann. Se. Nat. 1844, 1. р. 279. 
| Pringsheim, Jahrbuch für wissensch. Botan. 1871, viii. р. 194. 
4 Frank (in Jahrbuch, 1875, t. x. p. 204) also says that the petalline tubercles are at first not distinct from the 
stamens. 
252 
