Pentachaeta bellidiflora
| Pentachaeta bellidiflora | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Tribe: | Astereae |
| Genus: | Pentachaeta |
| Species: | P. bellidiflora |
| Binomial name | |
|
Pentachaeta bellidiflora (Greene) D.D. Keck |
|
| Synonyms | |
|
Chaetopappa bellidiflora (Greene) Keck |
|
Chaetopappa bellidiflora (Greene) Keck
Pentachaeta bellidiflora (white-rayed pentachaeta or Whiteray pygmydaisy) is a Californian wildflower in the genus Pentachaeta of the (Asteraceae) family. It is included in both the state and federal lists of endangered species.
It is endemic to the San Francisco Bay Area of California, United States, and occurs only at altitudes less than 620 metres (2,034 ft). P. bellidiflora is found chiefly on rocky, grassy areas. The conservation status of this species was, as of 1999, characterized by a declining population, with a severely diminished and fragmented range. The specific bellidiflora refers to the similarity of the flowers with those of common daisies (Bellis).
Pentachaeta bellidiflora is a small annual wildflower growing from a slender taproot, which, although it appears smooth, is actually covered by fine hairs. The sparsely hairy stems may number between 6–17 cm (2–7 in) in length and are typically simple, or branching in the lower half of plant. They are erect, generally flexible, and of green to reddish color. White-rayed Pentachaeta leaves are normally narrowly linear, ciliate (fringed with hair) and green, measuring less than 4.5 cm (1.8 in) long and one millimeter wide. Upper and lower leaf surfaces are smooth.
The terminal inflorescences number four or five solitary, roughly circular heads per plant. Peduncles are wispy, with bell-shaped involucres measuring 3 to 7 millimeters, and they range from glabrous to short-haired. Like all of its genus, P. bellidiflora has green phyllaries in two to three generally equal series, lanceolate to obovate, with margins widely scarious (dry and membranous), and a naked receptacle. The yellow corollas are five-lobed, and each of the 16 to 38 disk shaped florets (per head) has linear, acute style tips. They may be slightly red-tinged underneath. Fruits are 1.5 to 3.0 millimeters in diameter and are generally compressed in an oblong to shape; they are typically covered with small hairs. The plant presents fragile pappuses with five or fewer slender bristles, slightly expanded at the base. Flowering season ranges from late March until late June. From a chromosomal standpoint, the species is diploid, (contains one set of chromosomes from each parent), and has 2n=18.
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