BOTN 201 - Department of Biology - TAMU
Images of the Navasota Flora - 26 March 1995
This has been our annual 'green week', a conspicuous transition from winter dormancy to the first photosynthesis of Spring. Throughout the Navasota Valley, terminal meristems of deciduous woody dominants have burst through their bud-scale containment to produce leafy shoots. Here is the 'green week' status of several local species as of the 26th of March, 1995.
The 'mother of all Photinias', located between Butler Hall and the 'Old Chemistry Building' is covered with inflorescences. A close look at these reveals this element of the local ethnoflora (Photinia serrulata) to be a member of the Rosaceae. This is indicate by the presence of a pentamerous perianth with numerous stamens and a 'floral cup' or hypanthium. These flowers are epigynous and, when mature, will produce a fruiting structure known as a pome. Thus, Photinia is clearly placed - with apples and pears, in the subfamily Maloideae.
A common inhabitant of woodland margins and openings in the Post Oak Savannah, the Star Grass (Hypoxis hirsuta is now moving into full bloom. As is the case with most members of the Amaryllidaceae, the flowers of this species show little differentiation between perianth whorls - the 3 sepals of the calyx are quite similar to the 3 petals of the corolla. The term tepal is often applied to perianth parts when all tend to be 'petaloid'.
The 'Indian Paintbrush' (Castilleja indivisa - Scrophulariaceae (Asteridae)), in rosette earlier this year is now in full flower. As is the case with many taxa of this large and diverse family floral expression is marked by complex structural adaptations. The striking 'red blanket' produced by Castilleja indivisa populations inhabiting local roadsides and meadows is, for instance, not a product of the flower. A close look reveals that this intense coloration is produced by bracts subtending each flower. The two calyx lobes are tinged with pink and the sympetalous, zygomorphic corolla of Castilleja indivisa (a mark of most Scrophulariaceae) is whitish. This Castilleja corolla terminates with an irregular extension known as a galea.
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Last updated by HDW on 27 March 1995