a s a d a R a o ,3 M . H. M e n g e s h a ,3 a n d D . E . B r i n k 2Paspalum scrobiculatum is widely distributed in damp habitats across the Old World tropics. It is harvested as a wild cereal in w est Africa and in India. The species was dom esticated in India som e 3,000 yr ago. It is grown in India from Kerala and Tamil N adu in the south, to Rajasthan, U ttar Pradesh and West Bengal in the north. K odo millet is variable but lacks racial differentiation. The species was apparently dom esticated across its range o f present-day cultivation. Hybridization with wild P. scrobiculatum, which commonly invades fields o f kodo millet, obscures racial differentiation. W eedy kodo is harvested with the crop, making it difficult to distinguish wild and cultivated com plexes o f P. scrobicula tum. Wild, w eed and cultivated kinds m erge in all characters studied.The genus Paspalum (Gramineae) includes some 400 species that extend across the warmer regions of the world. Paspalum scrobiculatum L. occurs throughout the Old World tropics. It is cultivated in India. Cultivated plants are grown as annuals, but many cultivars root at the lower nodes and, under favorable con ditions, continue to produce culms after the older shoots have flowered and ma tured their inflorescences. Wild P. scrobiculatum is perennial. In southern India wild plants invade fields of planted kodo millet, and the spikelets of these weeds are often as large as those of the crop.Paspalum scrobiculatum occurs in moist or shady places across the tropics and subtropics of the Old World. The species is recognized, as demonstrated by Clayton (1975), to include the African P. orbiculare Forst. f., P. polystachyum R. Br., and P. cartilagineum Presl with usually smaller spikelets (1.8-2.5 mm long) than those of Indian wild specimens (2.5-3.5 mm). These taxa merge com pletely, not only in spikelet morphology, but also in overall inflorescence mor phology and vegetative traits. Plants are slender to stout, up to 90 cm tall, and often root from the lower nodes. Leaf blades are linear, glabrous or pubescent, up to 40 cm long, with the basal leaf sheaths glabrous or pilose. Inflorescences are composed of rarely more than 5 racemes (3-7) that are alternately arranged on a short to elongated primary axis. Racemes are up to 13 cm long, with the subsessile spikelets arranged in 2 rows along one side of a flattened rachis. Spike lets are glabrous, orbicular to broadly elliptic in outline, conspicuously plano convex, 1.8-3.5 mm long, and never awned. The lower glume is absent, and the upper glume is as long as the spikelet. The lower lemma is almost flat, more or less membranaceous and without a palea or floret. The upper lemma is crustaceous, often brown and shiny when grains are mature, and embraces the crustaceous palea. The grain is elliptic-orbicular in outline and 1.5-2.5 mm long.

a s a d a R a o ,3 M . H . M e n g e s h a ,3 a n d D . E . B r in k 2 Two species o f Echinochloa are grown as cereals. Echinochloa crusgalli is native to tem perate Eurasia and was dom esticated in Japan som e 4,000 yr ago. Echinochloa colona is widely distributed in the tropics and subtropics o f the Old World. It was dom esticated in India. Echinochloa colona is m orphologically al lied to E. crusgalli, but hybrids betw een-them are sterile. Echinochloa colona differs consistently from E. crusgalli in having sm aller spikelets with membran aceous rather than chartaceous glum es. H ybrids between wild and cultivated taxa o f E. colona and betw een those o f E. crusgalli are fertile. Cultivated E. colona is variable. It is grown as a cereal across India, Kashm ir and Sikkim. Four m orphological races are recognized, although these do not have geograph ical, ecological or ethnological unity. R ace laxa is confined to Sikkim where races robusta, intermedia and stolonifera are also grown. In India, races robusta, intermedia and stolonifera are often grown as mixtures, and Echinochloa is som etim es grown as a mixture with other cereals, particularly Setaria italica (foxtail millet) or Eleusine coracana (finger millet). The species is p lan ted on p o o r soil, and som e cultivars m ature in less than 2 mo. They hold considerable prom ise as cereals fo r the sem iarid tropics.

Finger millet (Eleusine coracana (L.) Gaertn. subsp. coracana) is cultivated in eastern and southern Africa and in southern Asia. The closest wild relative of finger millet is E. coracana subsp. africana (Kennedy‐O'Byrne) Hilu & de Wet. Wild finger millet (subsp. africana) is native to Africa but was introduced as a weed to the warmer parts of Asia and America. Derivatives of hybrids between subsp. coracana and subsp. africana are companion weeds of the crop in Africa. Cultivated finger millets are divided into five races on the basis of inflorescence morphology. Race coracana is widely distributed across the range of finger millet cultivation. It is present in the archaeological record of early African agriculture that may date back 5,000 years. Racial evolution took place in Africa. Races vulgaris, elongata, plana, and compacta evolved from race coracana, and were introduced into India some 3,000 years ago. Little independent racial evolution took place in India.

Data indicate a non-random distribution of nectar among plants in a population of Delphinium nelsonii Greene. More plants than expected had no nectar (blanks) or large amounts of nectar (bonanzas), while fewer plants than expected had intermediate amounts of nectar. This bonanza-blank pollinator reward schedule suggests that a high proportion of the nectar obtained by pollinators comes from occasional bonanza plants encountered in the population.