BOTN 201 - Department of Biology - TAMU
Images of the Navasota Flora - 23 April 1995
One of 8 Texas Vaccinium species ('Blueberry' - Ericaceae), V. arboreum ('Farkleberry' or 'Sparkleberry') is - like many of the Navasota Flora's forest species - near the western extent of its range in the Navasota Valley. This is one of the most common understory shrubs of our upland Post Oak woodlands. A close look at a "Farkleberry" flower reveals the classic urceolate, sympetalous corolla of many Ericaceae and also epigyny, a condition that occurs in many genera of the family.
The Polygalaceae (Rosidae) is represented only by the genus Polygala ('Milkwort') in Texas. The petaloid, 'winged' sepals, combined with connation and zygomorphy in the corolla, give these little plants an orchid-like appearance. There are 25 Polygala species in Texas.
The Wood Rush, Luzula bulbosa (Juncaceae), in full flower last month, is now setting fruit. This Luzula infructescence shows the capsular fruit of the Juncaceae, with a single seed in each locule of the syncarpous gynoecium. Seed polymorphism (note capsule with all 3 seeds above and to the left of the marked capsule) probably reflects some type developmental abortion.
The other local genus of the Juncaceae - Juncus - also shows a rough vegetative similarity to related families of the Cyperales - the grasses (Poaceae) and the sedges (Cyperaceae). Two features - most evident in fruiting plants - clearly identify the family as an element distinct from the Cyperales. The flowers have a perianth of 6 sepals and these subtend a capsular (more than 1 seed) fruit at maturity. Flowers of the Juncaceae are, however, quite small and family identification requires a close look.
The Navasota Flora is now moving from Spring to early Summer mode. This transition is marked by emergence of the Asteraceae. A conspicuous genus, Erigeron ('Fleabane'), is coming into flower along roadsides this week. It is marked by its radiate capitulum which features an unusually large numer for ray florets with unusually thin corollas.
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Last updated by HDW on 25 April 1995