PLANT TISSUES 
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multicellular, non-glandular (simple) or glandular. The non- 
glandular hairs may be of various shapes, viz.: clavate (club-shaped) 
as on Rhus glabra fruits ; stellate (or star-shaped) as on Deutzia 
leaves; candelabra-shaped, as on Mullein leaves; filiform as on 
Hyoscyamus, Belladonna and Digitalis leaves; hooked, as on stems 
of Phaseolus multiflorus or Hops; barbed, as on the stems of Loasa 
species; or tufted, as found on the leaves of Marrubium vulgare. 
They may be simple as in Cotton, etc., or branched as in Hyoscyamus 
muticus. 
The glandular hairs comprise those whose terminal cell or cells are 
modified into a more or less globular gland for gummy, resinous or 
oily deposits. They are generally composed of a stalk and a head 
region although rarely the stalk may be absent. The stalk may be 
unicellular, bicellular or uniseriate (consisting of a series of super¬ 
imposed cells). The head varies from a one- to many-celled struc¬ 
ture. The drug Lupidin consists of the glandular hairs separated 
from the strobiles of Humulus lupulus. 
Scales are flat outgrowths of the epidermis composed of one or 
several layers of cells. They occur attached to the stipes 4 of Aspid- 
ium, Osmunda and other ferns, where they are called “chaff scales.” 
They are also found on a number of higher plants. 
Plant hairs are adapted to many different purposes. They may 
absorb nourishment in the form of moisture and mineral matter 
in solution, e.g., root hairs. Those which serve as a protection to the 
plant may be barbed and silicified, rendering them unfit for animal 
food, or, as in the nettle, charged with an irritating fluid, penetrating 
the skin when touched, injecting the poison into the wound. A 
dense covering of hairs also prevents the ravages of insects and the 
clogging of the stomata by an accumulation of dust. They fill an 
important office in the dispersion of seeds and fruits, as with their 
aid such seeds as those of the milkweed and Apocynum are readily 
scattered by the wind. 
The reproductive organs of many Cryptogams are modified 
hairs, as the sporangia of Ferns. 
ENDODERMIS 
Endodermis is the “starch sheath” layer of cells, constituting 
the innermost layer of the cortex. In Angiospermous stems it 
