374 Scott Elliot. — On the Fertilisation of South 
Pleetranthus Melleri, Bkr . 
The flowers are small and mauve with dark spots (honey- 
guides) on the upper lip. The four stamens in this species 
roll forward and dehisce together at a point opposite the 
entrance to the corolla-tube. Subsequently they continue 
the unrolling process and bend down on each side of the 
lower lip. The stigma then elongates and rises slightly. 
The nectary consists of both an anterior and a posterior ridge. 
Pleetranthus ealycinus, Bth. 
The corolla is covered externally with woolly hairs and 
has a very peculiar shape ; the tube is extremely deep and 
its axis is inclined to that of the pedicel. The lower lip has 
the two sides bent up so as to have a boat-shaped appearance, 
something like the carina of a leguminous flower : when at 
rest the two edges of this carina fit between the lateral petals 
which form cushion-like ridges on either side of the broad 
opening of the corolla-tube and so completely close it. The 
essential organs are contained in this carinoid lower lip. An 
insect must alight on this carina or lower lip and force it down, 
and whilst doing so the stamens emerge and dust its sides 
with pollen, whilst in older flowers it must also be touched by 
the stigma. The lower lip flies back elastically after depres- 
sion and it requires considerable force to press it down. The 
nectary is chiefly developed on the front of the ovary and a 
small pinching-in of the corolla just before it forms a sort of 
cup in which honey accumulates. The woolliness of the 
corolla is to prevent insects biting an entrance to the tube. 
I found many flowers with a small hole at a point just above 
the nectary, and caught a small fly with a proboscis x 3 ^ of an 
inch long sucking through these holes. 
Pleetranthus laxiflorus, Bth . 
This species is remarkable for the sudden bend at right 
angles in the corolla-tube. The lower lip has the same boat- 
shaped appearance as in P. ealycinus and also the same tension 
which makes depression hard to produce. I watched a bee 
enter and could see that it required considerable force to 
