AN INVESTIGATION OF LOBELIA GIBB08A AND LOBELIA DENTATA. I. Mycokrhiza, Latex System and General Biology. By Lilian Fraser, B.Sc. (Forty-four Text-figures.) [Read 25th November, 1931.] Introduction. — The mature plant. — The seedling stage. — The root system and mycorrhiza. — The shoot system. — The latex system. — General biology, experiments and observations. — Discussion. Introduction. The investigation here reported was commenced in Adelaide early in 1916. Miss A. Rennie, working under the direction of Professor Osborn, began an examination of Lobelia gibbosa Labill., and made a study of its latex system and a preliminary examination of the fungus present in its roots. She also made a number of field notes on the growth habits of the plant, and some experiments. This work was not published. In the summer of 1929 Professor Osborn noticed that Lobelia dentata Cav. growing in the Sydney district had a number of interesting and peculiar features in common with Lobelia gibbosa; and on his advice an investigation was made of both species, and the work previously done by Miss Rennie was confirmed and extended. The present communication includes the results of both investigations, Miss Rennie having generously handed over her notes, drawings and preparations to the author, who wishes to acknowledge her indebtedness for them. Text-figures 37-40 are from drawings made by Miss Rennie. The author alone is responsible for any opinions expressed. The Mature Plant. Lobelia gibbosa Labill. is reported for all the Australian States, including Tasmania. In South Australia, where part of the work was carried out, it is reported by Black (1922) as occurring on Kangaroo Island, Yorke and Eyre Peninsulas and probably in the south-west. The material for the present work was collected in the scrub at Mt. Lofty, near Adelaide. Bailey (1900) and Ewart (1930) distinguish three varieties of this species of Lobelia, the one here described corresponding to var. microsperma, but Black (1922) gives microsperma as a synonym for gibbosa and distinguishes no varieties. Ewart considers that the species is composed of a complex of hybrids. L. gibbosa is an annual herb, growing in both sandy and clay soil, often in colonies. The stem is erect and usually unbranched, except sometimes in the region of the inflorescence. It is somewhat turgid and succulent, with a length underground of 2-5 cm., occasionally more. The leaves are all cauline and vary
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