TML> Ghosh, Nabarun*, A. Chatterjee, and Don W. Smith. Acacia, Albizia, Cassia and Dalbergia are four genera of Leguminosae comprising trees that produce valuable forest products. Ultrastructural features obtained from SEM often constitute a valuable source of information in diagnosing already circumscribed taxa and/or in phylogenetic inference. We carried out micromorphological studies on seeds using a light microscope and SEM. We cut transverse and longitudinal sections of the seeds and observed the sections from different regions of seeds: midseed, near the hilum and two distal ends. SEM study on the seed sections revealed the size, shape, and number of tiers and cellular organization of the epidermis, hypodermis, endosperm and internal structural details. We observed the distinctive anatomical features of each species by which they could be differentiated from the other species with SEM (Ghosh, 1997). We observed epidermal cells that were round, columnar, cuboidal or sometimes elliptical. The characteristic presence of "hour glass cells" was noted in the hypodermis of some species of Caesalpiniae. Two species of Cassia (siamia and spectabilis)contained hourglass cells with variation in number and orientations. We observed a multiseriate epidermis with double palisade layer in three species of Cassia (glauca, siamia and spectabilis). In 3 species of Dalbergia the epidermal layer was but the hypodermal layer was broad having a pattern characteristic to each species. Stomata were evenly distributed in the storage tissue of seeds of A. falcataria and D. sissoo. Cross sections of these seeds appeared green under a dissecting scope indicating possible photosynthetic activities in the storage tissue. Endosperm pattern was different in Albizia falcataria and A. lebbeck, D. assamica, and D. latifolia. Again, in the two species of Cassia, (siamia, spectabilis) the endosperm pattern was species specific. We also studied the seed coat pattern that added new diagnostic information on the tree species.

Key words: Acacia, Albizia, Cassia and Dalbergia, Leguminous trees, Seed anatomy, SEM