Page 8 - Pharmacognosy-II (06-PG 303)

2- Drupe : The epicarp is leathery, mesocarp is fleshy. The endocarp is hard
woody enclosing a single seed as olive.

Aggregate Fruits :
These are formed of a collection of fruitlets arranged on a single receptacle.

They may be a group (etaerio) of achenes on a fleshy receptacle. e.g. Strawberry; or
a group of follicles on a dry receptacle, e.g. star anise.
Macroscopical Characters :

The fruit shows two Scars: one at the base marking the attachment to the
stalk, the other mostly apical marking the remains of the style and stigma.
The surface of the fruit may be: smooth, glabrous (Caraway), pubescent (Anise),
granular (Citrus), spiny (Stramonium), striated (Senna) or ridged (Umbelliferae).
The sutures may be well marked as one line (dorsal side) or as two lines (ventral
side).
Microscopical characters of Fruits :

The fruit consists of two parts : (1) The seed (2) (Pericarp) fruit wall =
Epicarp, Mesocarp and Endocarp.
1- The epicarp or outer epidermis :

It may contain Ca Ox. Crystals and trichomes.
Trichomes may be present : nonglandular and unicellular (Anise, Senna),
multicellular (Cumen), glandular (Compositous fruits).
Hypodermis : may be present or not. It may be one or several layers :
Parenchymatous (Capsicum minimum), Collenchymatous, Vanilla and Citrus fruits)
and Sclerenchymatous interrupted by parenchyma (Black pepper).
2- The Mesocarp :

It may be very thin as in achenes or several layers in fleshy fruits, and is
mainly formed of parenchymatous cells and traversed by vascular strands. It may
show Oil cells (Black pepper), Oil glands (Citrus fruits), Vittae (Umbelliferous
fruits) latex vessels (Poppy), Ca ox (Hyoscyamus, capsicum, bitter orange peel),
Vanillin crystals (Vanilla pods). Hesperidin crystals (Citrus fruits), Starch
(Black pepper).
3- The Endocarp or inner epidermis :

It is formed of a single layer, occasionally accompanied by one or more
hypodermal layers. It may be made of parenchyma (Colocynth) stone cells (Black
pepper, Almond …), islands of lignified sclereids distributed in parenchyma
(Capsicum), may grow into the cavity of the fruit as hair-like secreting cells
(Vanilla) or as multicellular emergencies that become filled with juice (Citrus

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