THE ANDUCECIUM OF MENTZELIA. 217 
r 
in Agrimonia and Poterinm tliey are compound. It is unnecessary to 
enter more fully into the description of these arrangements, as the 
diagrams I have constructed will render them perfectly intelligible,* 
In accordance with the foregoing remarks, the staminal arraufire- 
ments in those Rosacece of which the development is known, may be 
classified under two principal types, as follows : — 
I. Aldiemilla'type, — Single wJiorl ol stamens alternate witli the sepals. 
No true corolla. 
(a) Stamens simple: eg, Alcheynilla (Fig. 7). 
{h) Stamens compound, confluent, with petidoid apices : e.g^ 
Euhus (Fig. 8) ; Rosa (Fig. 9) ; Geum (Fig. 10) ; Fragarla, 
Spircea, etc. (Fig. 11). 
II. Aremonia-tgpe. — Single wliorl of stamens superposed to the sepals. 
With or without a true corolla. 
(1) Witli a true corolla. 
(a) Stamens simple : e,g, Aremonia (Fig. 3). 
(V) Stamens compoimd : €,g. Agrimonia (Fig. 4). 
(2) Corolla absent. 
(c) Stamens simple: e,g, Sanguisorha (Fig. 5). 
id) Stamen;* compound, confluent: e,g, Poterium (Fig. 6). 
It will be seen from the above that, if I am cori*ect in my concln- 
sions, AlcJiemilla bears to Rubus^ Geum^ or Fragaria^ in staminal 
arrangement, the same relation as Jremonia does to Agrimonia, or 
Sanguisorha to Poterinm. This tends strongly to confirm Payer's 
opinion, in which he followed the older botanists, tliat AlcJtemlla lias 
really closer affinities with the Poteiitillidm than with the SanrjniHOrbe(p^ 
with which it has been more recently associated. 
Perhaps a iliird^ and possibly diplostemonous, type of Rosaceous 
andra^cinm is to be found in those genera {Sibbaldia, etc.) iuclurled 
in the tribe CharncBrJiode^^ but these require careful organogenic inves- 
tigation. 
* The analogy of Sangnisoi^ba and Poterium, with Aremonia and Agrimonia^ 
indicated by tliis association, does not, perhaps, rest upon a very secure foun- 
dation. I Iiave followed Payer, who remarks that *' les Pimprenelles doivent 
^tre regardees comme les Aigi'emoines tetram^res dont les petales ont avorte." 
It is, however, with considerable hesitation that I have done so ; because, if in 
Sanguisorha the sepals and stamens are developed in four pairs, in regular de- 
cussate succession, as Payer's researches seem to indicate, it is difficult to jus- 
tify the assumption of an abortion of petals alternate with tlie sepals. Our 
knowledge, however, of the analogy between the arrangement of floral parf^ and 
that of ordinary leaves upon the stem, is as yet too imperfect to allow of any 
definite conclusion upon the subject. 
VOL. III. [JUIY 1, ISfio.] Q 
