Convergent inflorescence morphology in the mimosoid legume genera Parkia (right) and Dichrostachys (left). Parkia nitida Miquel from Ecuador has pendant inflorescences specialized for bat-pollination. The basal flowers are sterile, with white staminodia forming a fringe that overhangs the nectar-producing flowers; the yellow distal flowers are bisexual. Inflorescences of Dichrostachys cinerea (L). Wight and Arnott also have a staminodial fringe, but the staminodia are rose colored when the flowers first open, and gradually change to white postanthesis. These inflorescences also lack specialized nectar-producing flowers, and are presumably entomophilous.
Gentiana sino-ornata Balf f. (Sect. Monopodiae) distributed in the mountains of southwest China and adjacent Burma, is one of the most magnificent gentians in the world. It was introduces into Europe in the early decades of this century and has contributed much to the botanical gardens of Europe. However, the individuals growing in their native land look more lovely. The photo was taken from Aba (3,200 m) Sichuan, China.
White-flowered form of Syringa vulgaris from the Arnold Arboretum of harvard University. Several hundred cultivars of lilacs were developed from 22 wild species through extensive hybridizatino and artificial selection. The parentage of several of these hybrids was confirmed using restriction site analysis of both chloroplast and nuclear ribosomal DNA.
The golden heads of Balsamorhiza and Wyethia covering the foothills herald spring in Utah's Wasatch Mountains. Balsamorhiza macrophylla, the cutleat balsamroot (shown here), commonly grows interspersed with B. sagittata (arrowleaf balsamroot) and W. amplexicaulis (mule's ear) on hillsides and in open woods.
This rare member of the ginger family (Zingiberaceae) is restricted to monsoonal forest margins and grasslands in central Myanmar. The conspicuous floral parts are highly modified sterile stamens, or staminodia. Results of phylogenetic analyses based on molecular data have provided new information on relationships among the 50+ genera of the family and form the basis for a new classification as well as setting the stage for investigations of the biogeographic history and floral character evolution in this tropical group of monocots.
Tristerix penduliflorus (Loranthaceae) is a bird-pollinated mistletoe
that occurs in dry, high elevation (3700 m) habitats from southern Peru to Bolivia.
This plant, parasitic on Schinus (Anacardiaceae), was photographed near
Maras, Departamento Cuzco, in southern Peru (scale: 3.83× unopened flower
buds are typically 3.7 cm long). Although the flower color pattern suggests affinity
with other Peruvian species, molecular data indicate that T. penduliflorus
is related to three Tristerix species with more southern distributions.
One of these southern species from central Chile, T. aphyllus, appears
to have arisen in sympatry from T. corymbosus, an event accompanied by
a host switch driven by the behavior of a seeddispersing bird.
Flower of Trigonidium egertonianum, an orchid in the subtribe Maxillariinae.
Flowers of Trigonidium are pollinated by pseudocopulation by meliponine
bees attracted to the bluish petal apices; the bees attempt to copulate with the
flowers and become trapped in the funnel-shaped flowers. On the basis of molecular
data, Trigonidium was found to be embedded in the large polyphyletic
Variation in hip (fruit) morphology in rose species (Rosa spp., Rosaceae).
In traditional Rosa classifications, this morphological variation is
utilized for sub-division into subgenera, sections, and subsections. However,
the genus Rosa has a complex evolutionary history that is not always
adequately reflected in morphological characters. As a result, morphology can
be an unreliable indicator of phylogenetic relationships in Rosa.
Marattia howeana (W.R.B.Oliv.) P.S.Green, a rare endemic to Lord Howe
Island with only a few known remaining populations. Several marattioid fern
species, including M. howeana and the Hawaiian endemic M. douglasii
(C. Presl) Baker, are seriously threatened by introduced feral pigs who favor
the sweet fleshy rhizome as a food source. The fully fused synangia (fused sporangia,
ca. 3–5 mm in length), characteristic of Marattia s.l., are captured
in this photo just at the stage of dehiscence. This photo was taken from live
material grown at Humboldt State University, Arcata, California, where new methods
for efficient asexual propagation of marattioid ferns are currently under development.
For further details, see Murdock: Phylogeny of marattioid ferns (Marattiaceae):
inferring a root in the absence of a closely related outgroup, American
Journal of Botany, Volume 95, Issue 5, pages 626-641, http://www.amjbot.org/cgi/content/short/95/5/626.
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