MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY ( 
FLOWER-AXIS. 
The so-called calyx of the RosackAk and other calycifloral families consists of two 
distinct parts, viz., the upper free portion (the sepals) which constitutes the calyx as the 
term is ordinarily understood, ?. ¢., the outer set of floral envelopes, and a lower, more or 
Jess cuplike portion. This has generally been regarded as the gamosepalous part of the 
calyx, and is so described in almost all our American systematic works. It is, however, 
without doubt of an entirely different origin. With the exception of, in some cases, per- 
haps, a very small portion at the rim of the cup (i. ¢., just at the base of the free sepals ), 
the whole of the so-called gamosepalous part of the calyx must be regarded as belonging 
to the flower-axis. This view is now held by most of the prominent systematists and 
morphologists in Europe as Baillon,' Henslow,? Wiesner* and most of the authors of 
“Die Natuerlichen Pflanzenfamilien,” edited by Engler and Prantl, viz., Engler,* 
Focke,® Gilg,® Raiman,’ Koehne,® Schimper,” Niedenzu,” and Brandis." 
Some of the reasons for this view are as follows : 
1. The petals and stamens, which are generally regarded as homologues of foliage 
leaves, are borne on the margins of the cup inside the calyx-lobes. If the cup is to be 
regarded as the lower part of the united sepals, one set of phyllomes would be borne on 
the upper surface of another set, which would be a very unnatural condition according 
to our general conceptions. If the cup is regarded as a modified flower-axis, the ex- 
planation of the arrangement of stamens, petals and sepals is very simple. 
2. If the cup is regarded as the result of the adnation of the lower portions of the 
sepals, petals and stamens, the difficulty is not removed. The petals fall off by a joint 
at their insertion at the margin of the cup. This point should either be the lower end 
of the petiole or else the petal should represent only the leaflet of a unifoliolate leaf. 
In the first case it would be borne on the calyx as above. In the second case, the 
difficulty would be that the leaflets in Potentilla and most genera are not deciduous, nor 
eyen jointed to the rachis. We should also find a continuation of the leaf downward 
representing the rachis. There isa kind of continuation in the form of a fibro-vascu- 
lar bundle, but this unites with those from the antipetalous stamens before it reaches the 
bottom of the cup. So also the fibro-vascular bundles of the sepals unite with those of 
the antisepalous stamens. If the three sets of organs were completely united and all 
1 Histoire des Plantes, 1: 345-6. 7Vol. 3: part 7, 199 (Onagraceae). 
2 The Origin of Floral Structures, 96. 8 Vol. 3: part 7, 1 (Lythraceae). 
3 Elem. Wiss. Bot. 2 : 307. SVol. 3: part 7, 42 (Rhizophoraceae). 
‘Vol. 3: part 2a, 41 (Saxifragaceae ). 107, ¢, 57 (Myrtaceae). 
5 Vol. 3: part 3, 4 ( Rosaceae. ) 117, e. 106 (Combretaceae). 
6 Vol. 3: part 6 a, 100 (Loasaceae). 
