Alston's observations were founded on what occurred in certain unisexual plants, such as Mercurialis, Spinach, Hemp, Hop and Bryony.
Seedling plants from the cultivated vines often produce unisexual flowers, thus reverting to the feral type.
By the suppression of the verticil of the stamens, or of the carpels, flowers become unisexual or diclinous, and by the suppression of one or both of the floral envelopes, monochlamydeous and achlamydeous flowers are produced.
Evergreen shrub with flattened leaf-like cladodes, native in the southerly portion of England and Wales; the small flowers are unisexual and borne on the face of the cladode; the male contains three stamens, the filaments of which are united to form a short stout column on which are seated the diverging cells of the anthers; in the female the ovary is enveloped by a fleshy staminal tube on which are borne three barren anthers.
In unisexual flowers it is not uncommon to find vestiges of the undeveloped stamens in the form of filiform bodies or scales.
A few species, as we have seen, are monoecious or dioecious, while many are polygamous (having unisexual as well as bisexual flowers as in many members of the tribes Andropogoneae, fig.
The flowers are unisexual and monoecious, the numerous males borne in thick catkins proceeding from the side of last year's shoot.
The flowers spring in branching spadices from the axils of the leaves, and as the trees are unisexual it is necessary in cultivation to fertilize the female flowers by artificial means.
The flowers spring from, or are enclosed in, a spathe, and are unisexual and regular, with generally a calyx and corolla, each of three members; the stamens are in whorls of three, the inner whorls are often barren; the two to fifteen carpels form an inferior ovary containing generally numerous ovules on often large, produced, parietal placentas.
These are followed by the inflorescence, a fleshy spadix bearing in the lower part numerous closely crowded simple unisexual flowers and continued above into a purplish or yellowish appendage; the spadix is enveloped by a leafy spathe, constricted in the lower part to form a chamber, in which are the flowers.