What is the fine-grained topic of the following text: Inner tepals enlarged in fruit; valves broadly ovate, 3.5-6 × 3-5 mm, all with tubercles, rarely only 1 valve bearing a tubercle, conspicuously net veined, base nearly truncate, margin entire, rarely weakly erose, apex obtuse to subacute; tubercle ovate, 1.5-2 mm. Only return the topic.
Plant Morphology