218 THE ANDKCECITj'M 0¥ mentzelia. 
EXPLANATION OF PLATE XXIIT. 
In the diagrams the sepals are shacled : the true petals in outUne, The sta- 
mens are represented by black spots, of which the larger indicate the older, the 
smaller the younger ones. Tlie false petals, or petaloid staminodes, are indi- 
cated in black, Uke the stamens. The epicalyx, wliich is proper to some of the 
Eosaceous forms represented, is omitted, partly to make the diagrams of more 
general application, and partly to avoid unnecessary and perhaps confusing 
detail. 
Fig. 1. Arrixugem.eni in. Mentzelia {LoasacecB), Calyx. Corolla. Stamens 
compound, confluent, saperposed to the sepals. 
Fig. 2. Arrangement m JBartonia {Loasacece), Essentially the same as in 
Menizelia : only, the apices of the staminal groups or compoimd stamens are 
developed as petaloid ataminodes. 
Fig. 3. Arrangement in Aremonia (Eosac€ce)\ Calyx. Corolla. Single 
whorl of simple stamens superposed to the sepals. 
Fig. 4. Arrangement in Agrimonia {Aremonia-type) . Tlie same as in ArC'. 
monia ; only, the stamens are compound. 
Fig. 5. Arrangement in Sanguisorba (^Aremonia-ii/pe). CoroUa absent. Of 
the four sepals, the antero-posterior pair are the older, the lateral the younger. 
Similarly the antero-posterior pair of stamens are the older, the lateral the 
younger. 
Fig. 6. Arrangement in Poterium {Aremonia-ft/pe). Corolla absent. Sepals 
4. Stamens 4, superposed to the sepals, compound, and confluent. 
Fig. 7. Arrangement in Alchemilla {Eosacece), Apetalous. Scpab 4. Sta- 
mens 4, simple and alternate vrith the sepals. 
Fig. 8. Rubus [Alchemilla'iype) . 
Fig, 9. Rosa (^Alehemilla-iype), 
Fig. 10. Geuni {AlcJiemilla-type) , 
Fig. 11. Fragaria, Spircea, Cotoneaster, etc, {Alchemilla-type). In tliis and 
the three preceding forms the symmetry is quinary. The stamens, as in Alche- 
fiiUla^ alternate with the sepals ; but instead of being simple, they are com- 
pound and confluent, with petaloid apices. No true petals. As the diagrams 
indicate, the staminal lobes vary in number in these forms ; but in aU the ten 
oldest stamens are disposed so that there is one on cither side of each petaloid 
Btaminode. 
Fig. 12, Section of young flower of Comarum palustre : ec, epicalyi j J, 
sepals ; p, the so-called petals (petaloid staminodes) ; st^ stamens of the first 
range, of which two accompany each "petal;" the other stamens have not 
yet appeared ; ax, convex extremity of the floral axis upon which the carpels 
afterwards appear. Ultimately, the staminal arrangement ia the same as in 
Fragaria (Fig. 11). 
