364 VARIOUS PLANT GROUPS 
peach (Fig. 94, page 89), plum (Fig. 95, page 90), cherry 
(Fig. 96, page 90), raspberry (Fig. 97, page 91), straw- 
berry (Figs. 98 I-III, page 92), and roses (Figs. 148 II, 
III, 298, pages 150, 151, 378), is seen to possess many 
features of floral structure resembling more nearly those of 
the crowfoot family than of any other family we have 
studied. 
Note in the formulas of Rosa, Fragaria, Rubus, Prunus, Cydonia, 
and Pyrus, given on pages 408, 409, that the floral envelopes are 
mostly in fives, while the essential organs are commonly numerous, 
and that all are free and distinct, except sometimes the carpels, 
which then, unlike poppy carpels, have axile placente. 
An unusual form of calyx is found in strawberries (Fra- 
garia). Here the sepals have stipules which coalesce in pairs so 
as to form what looks like a calyx upon a calyx, and is termed 
therefore an epicalyx.' The only other features not before 
encountered belong to the torus and the fruit. Throughout 
the family the torus is concave or cup-like, and it is mostly 
free as in peonies and our examples of the laurel family. In 
roses (Rosa) it completely envelopes the carpels, and be- 
comes fleshy and bright colored while the pericarps ripen 
into hard nutlets,? the whole forming a so-called ‘“‘hip.”’? The 
strawberry fruit consists mainly of the upper part of the 
torus,* much swollen and bearing numerous achenes. Rasp- 
berries have the upper part of the torus comparatively dry, 
and in fruit the pericarps finally separate from it. As these 
ripen, an outer layer becomes fleshy while an inner layer 
hardens like an olive stone. A fruit in which the pericarp 
is thus differentiated is called a ‘“‘stone-fruit”’ or drupe.* In 
raspberries and thimbleberries the little: drupes coalesce 
sufficiently to form a thimble-like mass after they separate 
from the torus. In blackberries, on the contrary, the little 
drupes remain attached to the part of the torus which bears 
1 Epi-ca’‘lyx < L. epi, upon. § | 
2 The hardening of the pericarp is expressed in the formulas by two 
inverted exclamation marks. 
3 A small ¢ to represent part of the torus is used in the formulas instead 
of the large capital. 
4 Drupe < L. drupa, a ripe olive. Cjj! 
