Notes on the Pollination of some South African Cycads. 267 
7 inches, while, on the other hand, if the grass is long or the plant, as is 
frequently the case, is growing in a " Kommetje," the cones may reach a 
height of 15 inches. These figures indicate that an attempt is made to 
lift the cone above its surroundings, and thus expose it to some extent 
to the action of the wind. 
The colour of the ripe male cone varies considerably. The sporophylls 
are covered externally by a coat of short matted tomentum of a brown or 
greyish-white colour. If, however, the cone has been exposed during its 
growth to the action of wind and rain, the tomentum gradually disap- 
pears, revealing the chlorophyll green of the underlying tissues. A slight 
but distinct odour is emitted while the pollen is being shed. It is difficult 
and possibly valueless to attempt to estimate the intensity of an odour, but 
I may say that it is not sufficiently powerful to affect my own olfactory 
nerves at a distance of more than about 2 feet. No insects have been 
observed to visit the cones, except the Lepidopter zerenopsis, sp., which de- 
posits its eggs freely on all parts of the plant and the neighbouring grasses. 
The caterpillars of this insect are very destructive of all our local Cycads, 
but the eggs are deposited almost throughout the year and without any 
reference to the production of cones. 
By the end of July (24th) the sporophylls of the more vigorous male 
cones begin to show signs of separating ; the process advances from the 
base upwards with extreme slowness. At the end of August (31st) those 
of the apical third are still tightly closed, and it is a fortnight later 
(September 14th) before they show signs of separating at the summit. 
Before this however (17th), the peripheral microsporangia of the lower 
sporophylls have turned brown and discharged their pollen. 
In all it takes from five to eight weeks for a single cone to discharge 
its pollen, and, allowing for variations in the time of ripening of cones, 
pollination may be effected any time during a period of ten weeks. It is 
not without significance that in this neighbourhood August and September 
are the windiest months of the year. Moreover, in June, July, August, 
and the first half of September there is little rainfall, and the vegetation 
of the grassland is at its lowest. The grasses are dry and shrivelled, and 
in many parts cropped short by cattle. At no other time of the year 
would a plant of the dimensions of Stangeria have so favourable an 
opportunity of disseminating its pollen by the agency of wind. 
On the 21st of September I kept four male cones under observation for 
about half an hour each. A strong westerly wind had sprung up, and its 
violence was great enough to cause the cones to sway from side to side 
and sweep out the pollen in clouds, which could be followed for a short 
distance moving in an upward direction. I exposed a number of micro- 
* The dates refer to the most vigorous specimen of one of 13 cones kept under con- 
tinuous observation from the 13th of July to October, 1912. 
19 
