32 CLASS-BOOK OF BOTANY. 
CHAPTER I. 
6. InpIAN Cruss, on GARDEN NAsturtIuM (Tropw@olum 
MAJUS). 
THis common plant, in one or other of its many varieties, is to 
be found in nearly every garden. Notice the lax straggling 
habit, the sueculent stems and the peltate leaves, by whose 
pétioles it appears to climb, though they are not nearly so 
sensitive as those of clematis. The surface is almost every- 
where glabrous; but the plant is very efficiently protected 
against most insect and other enemies by its pungent juice. 
From this pungency it has received its common name of Indian 
Cress, and by a curious confusion of ideas (not uncommon 
with gardeners, who are seldom botanists) it has also come to 
be called Nasturtium, which is the generic name of water- 
cress, but is quite inapplicable to our present species. 
The parts of the flower are easily made out. The calyx 
consists of 5 inferior sepals, connate at the base, of which 
the dorsal three unite to form a long spur or nectary. Of 
the 5 clawed petals 2 are perigynous*—1.¢., they are fastened 
to the calyx. The three lower are hypogynous, smaller than 
the upper two, and have the lower part of the limb fringed 
with long coloured flat hairs. The 8 stamens are hypo- 
eynous, aud have basifixed anthers. 
If you notice a series of flowers, from those just open- 
ing to others which are commencing to wither, you will 
observe that after they have expanded, two or three of the 
stamens bend upward so that their anthers lie in the path 
of any insect entering the flower. After all their pollen has 
been shed the filaments bend down out of the flower, and other 
anthers—ready to dehisce—move up and take their place ; 8° 
that for two or three days after opening any suitable insect 
visiting the flowers is almost certain to get dusted with 
pollen. After all the anthers have dehisced the style bends 
into the centre of the flower, and its stigma becomes viscid. 
By this contrivance self-fertilisation of the flower 1s vendere 
impossible. When first opened the flower is staminate 1 
function, and later on it is pistillate only. This contrivance, 
es ne ey see ee BP ee 
* Gr. peri, round about—the gynceciwm or pistil; which is the literat 
meaning of the term. 
