. The classification of flowering plants. Plants. 204 FLOWERING PLANTS [CH. 0®Q favoured by protogyny and the outward dehiscence of the anthers. In the most nearly allied genus, Rappia, the inflorescence is reduced to a spike of two opposite sessile flowers which, up to the time of flowering, are enclosed in the broad swollen sheaths of the two uppermost foliage-leaves, but are then raised to the surface by elongation of the peduncle. Pollina- tion is effected by the water, which floats the curved tubular pollen to the stigmas. There are two stamens and four sessile carpels, each with a solita
. The classification of flowering plants. Plants. 204 FLOWERING PLANTS [CH. 0®Q favoured by protogyny and the outward dehiscence of the anthers. In the most nearly allied genus, Rappia, the inflorescence is reduced to a spike of two opposite sessile flowers which, up to the time of flowering, are enclosed in the broad swollen sheaths of the two uppermost foliage-leaves, but are then raised to the surface by elongation of the peduncle. Pollina- tion is effected by the water, which floats the curved tubular pollen to the stigmas. There are two stamens and four sessile carpels, each with a solitary pendulous ovule (fig. 83, B). After fertilisation the carpels are each carried up on a stalk, while the peduncle also lengthens and may be spirally coiled (fig. 83, A). In Posidonia the elonoated stem bears a compound spike, the individual spikelets being borne in the sheathing bases of crowded leaf-like bracts. The lowerflowersof the spikelet are bisexual, the upper generally male. The bisexual have three stamens, with a broad leaf- like connective drawn out into a tail above the more or less separated anther-halves, which dehisce longitu- dinally on the outside. The single egg- shaped carpel contains one, rarely two, ovules. The whole plant is submerged, the thread-like (confervoid) pollen is floated to the fimbriated stigma. In Zostera (fig. 84) and Phyllospadix the flowers are on flattened spadices enclosed in the spathe- like sheath of the uppermost leaf Phyllospadix is dioecious. In Zostera the inflorescence is somewhat complicated. Its development is sympodial, while each lateral branch is united with the main axis up to the point at which its own fore-leaf is attached (fig. 84, A). On the upper surface of the flat mem- branous spadix w^hich terminates each branch are borne two. Fig. 83. A. Fruiting specimen of Ruppia mariti- via, var. spiralis, ^ nat. size. After Reichenbacb. B. Flo- ral diagi-am of Riippia. After Eicbler. C—E. Zannichel- lia. C. inflorescence, (?
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectplants, bookyear1904
