370 



HUTCHINSON'S POPULAR BOTANY 



FIG. 453. HENBIT (Lamium 

 amplexicaule). 



(a) Perfect flower ; (6) cleistogamic flow( 

 (c) section of (6). 



different plants. We might, indeed, 

 liken the androecium and pistil to tenants 

 in a house where the rooms are flowers 

 and the house itself is the plant. When, 

 as in the Oak (Quercus robur), Walnut 

 (Juglans regia), and Sweet Chestnut 

 (Castanea saliva, fig. 450), the male and 

 female flowers occupy the same house, 

 they are said to be monoecious (Greek 

 monos, one, and oikos, house) ; when, as in 

 the Juniper (Juniper us), Poplar (Populus), 

 and Willow (Salix. fig. 452), the sexes not 

 only occupy different rooms, but different 

 houses, being borne on distinct plants, the 

 flowers aie appropriately termed diwcious 

 (Greek di, two. and oikos). Hence, too, 

 the plants themselves are capable of 



sexual classification, some being male, others female, others bisexual, and 

 a fourth class, in which male, female, and hermaphrodite flowers are 

 found on one and the same individual, polygamous. 



With this digression, let us revert to the subject which led to it the 

 pollinating of a flower by its own anthers. The process of self-pollination 

 is the first stage of autogamy, which, as already explained, is the fecundation 

 of a flower by its own pollen ; and the whole process may, and sometimes 

 does, take place without the flower opening at all. It has, indeed, been 

 discovered by comparison of several closely allied flowers that the smaller 

 ones are frequently self-pollinated nay, that in some cases the same plants 

 which produce ordinary cross-pollinated flowers produce minute self- 

 pollinated ones which never open. Thus we may say that there are two 

 kinds of autogamous flowers those which open like ordinary flowers, and 

 those which remain closed. A glance at an example or two will make the 

 fact additionally clear. 



To take the last-named first. These, as the whole process is effected in 

 the closed flowers, are called cleistojamic, a name derived from the Greek 



Ideistos, closed, and gamos, 

 marriage. The Henbit 

 Dead-nettle (Lamium am- 

 plexicaule} offers excellent 

 examples of cleistogamic 

 flowers. The richly tinted 

 reddish-purple corollas of 

 the. expanded blossoms of 

 this not uncommon weed 

 are familiar to most persons 



FIG. 454. FLOWERS OF Myosotis IN SECTION. 



(a) Wood Scorpion-grass ; (6, c) Yellow and Blue Scorpion-gra 

 (d) Forget-me-not. 



