Biomorph Limosella aquatica L. and its contribution in stolon-rosette water grasses formation

Abstract

The paper presents comparative-morphological analysis of biomorphs Limosella aquatica L., stolon-rosette perennial mesophyte grasses (Viola odorata L.), and yearling vegetative hydrophytes (Stratiotes aloides L. and Hydrocharis morsus-ranae L.). It is shown that L. aquatica is a monopodial growing monocarpic with side stolon-rosette shoots and their systems with up to four branching orders. The primary shoot, as well as rosette parts of stolon-rosette shoots, is made of metamers with foliage leafs, axil complexes with differently sets of constituents: two collateral buds and/or their derivatives: flower buds/flowers/fruit, side stolon-rosette shoots or their systems. At the initial stage the shoot-forming mode of L. aquatica is similar to that of V. odorata: a monopodial rosette one with green assimilating leaves, flowers, and stolon-rosette shoots. But iterative branching of stolon-rosette shoots changes the shoot-forming mode of L. aquatica to a sympodial semirosette as in S. aloides, and especially in H. morsus-ranae. Biomorph L. aquatica combines the features of stolon-rosette perennial mesophyte grasses and stolon-rosette yearling vegetative hydrophytes: stolon-rosette shoot formation from axil buds, iterative branching, collateral buds, reduction inflorescence to one flower (S. aloides). Thus of habit L. aquatica can be viewed as a stage of perennial flower mesophyte plants’ shifting to life in water.