Lax Inflorescence Research Articles

Raphionacme pulchella (Periplocaceae), a new species from Mozambique and Zimbabwe

Raphionacme pulchella, a new species from Mozambique and Zimbabwe is described. This delicate species is recognized by the erect stems, linear leaves, multi-flowered lax inflorescences and the tiny purple flowers with tripartite corona lobes. R. pulchella resembles R. brownii Scott Elliot and R. chimanimaniana Venter & Verhoeven sp. nov., which are also erect, slender plants with linear leaves. All three species have pink to purple flowers, but the structure of these differ. R. pulchella has tiny flowers with tripartite corona lobes. R. brownii and R. chimanimaniana have larger flowers with simple corona lobes. R. pulchella inhabits grassland in Miombo woodland and montane forest.

GENECOLOGICAL STUDIES OF RUMEX CRISPUSL.

SUMMARYOpen‐pollinated seed was collected from several seed parents in each of 16 British populations of Rumex crispus L., representing the three principal variants of this species. Progeny of these seed parents (family lines) were grown in a garden trial, which revealed statistically significant differences between and within the populations sampled.(1) Coastal plants had denser inflorescences, fewer flowering stems, later anthesis and a greater development of corky perianth tubercles than inland plants.(2) Plants from riverine tidal mud at Tintern were distinct in their exceptional height, more or less uncrisped leaves, lax inflorescences, very early flowering and tubercle pattern intermediate to coastal and inland plants.(3) There was considerable variation between populations within coastal and inland habitats and within family lines. This spectrum of variation suggested that both outbreeding and inbreeding might occur in R. crispus.(4) Many plants from inland populations, with the exception of those from Tintern, flowered in their first year of growth, whereas populations from coastal areas and Tintern flowered in their second (or a later) year of growth.(5) There was evidence of gene flow between coastal and inland variants of R. crispus at ‘points of contact’, especially where coastal habitats had been disturbed. Plants from a few inland sites appeared to be hybrids between R. crispus and R. obtusifolius.(6) In cultivation, inland populations flowered consistently earlier than coastal plants. A similar difference in flowering time was recorded in a field study of a coastal area of Suffolk.

Pollen and pollination in the genus Eupatorium (Compositae)

Pollen of 18 of the 19 species of Eupatorium (sensu stricto) was examined with the scanning electron microscope (SEM). The species studied included the three dog fennels with dissected leaves and 14 species with undissected leaves. All species had echinate tricolporate pollen. One dog fennel, E. capillifolium, was found to have reduced spines relative to the other species. This one had other anemophilous characters, such as a longer stigma and greater stigma exposure, lax inflorescence branches, and smaller floral heads, suggesting an anemophilous pollinating system. Eupatorium compositifolium, another dog fennel, showed characteristics indicative of anemophilous ancestry, such as a long, greatly exposed stigmatic surface and lax inflorescence, but it had showy flowers as well as autecological features conducive to entomophily. All other species had reduced stigma lengths and exposure, stiffly upright inflorescence, and showy heads, all features indicative of entomophily. The advantage of acropetal over basipetal development of the inflorescence for anemophily is discussed. The dog fennels have acropetal, indeterminate development and the undissected leaf species have basipetal, determinate development; the latter of which is the basic pattern of inflorescence development in the Compositae.

A New Species of Desmodium from Africa

(L.) Benth. on the other. In its lax inflorescence, its bilabiate calyx and in the size and shape of the articles of its loments it is close to D. hirtum; in its general aspect, its unifoliolate leaves, appressed pilosity of stem, petioles and leaflet surfaces, it seems very close to some portions of the D. barbatum complex. The new species may be distinguished from its relatives by the characters indicated in the key which follows: